submission_id string | problem_id string | status string | code string | input string | output string | problem_description string |
|---|---|---|---|---|---|---|
s639233427 | p04046 | Accepted | h,w,a,b=map(int,input().split())
factorials=[]
inverses=[]
MOD=10**9+7
factorials.append(1)
curr=1
for i in range(1,h+w+1):
curr=(curr*i)%MOD
factorials.append(curr)
for i in range(h+w+1):
inverses.append(pow(factorials[i],MOD-2,MOD))
ans=0
for i in range(h-a):
ans=(ans+factorials[b-1+i]*factorials[h-2-i+w-b]*inverses[i]*inverses[b-1]*inverses[h-1-i]*inverses[w-b-1])%MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s316045630 | p04046 | Accepted | mod = 10 ** 9 + 7
fact = [1]
inv = [1]
for i in range(200000):
fact.append(fact[i] * (i + 1) % mod)
inv.append(pow(fact[i + 1], mod - 2, mod))
def ncr(n, r):
if n < 0 or r < 0 or n - r < 0:
return 0
return fact[n] * inv[r] * inv[n - r] % mod
h, w, a, b = map(int, input().split())
ans = ncr(h + w - 2, h - 1)
for i in range(min(a, b)):
ans -= ncr(h - a + b - 1, h - a + i) * ncr(w - b + a - 1, w - b + i)
print(ans % mod)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s979367224 | p04046 | Accepted | h,w,a,b=map(int,input().split())
mod=pow(10,9)+7
# コンビネーション、さらに高速。あらかじめO(N)の計算をすることでのちの計算が早くなる
def cmb(n, r, mod):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
g1 = [1, 1]
g2 = [1, 1]
inverse = [0, 1]
for i in range( 2, 200000 + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
ans=0
for k in range(1,h-a+1):
tmp=cmb(k-1+b-1,k-1,mod)
tmp*=cmb(h-k+w-b-1,h-k,mod)
ans+=tmp
ans%=mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s958216650 | p04046 | Accepted | def cmb(n, r, mod):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
mod = 10**9+7
size = 2*10**5
g1 = [1, 1]
g2 = [1, 1]
inverse = [0, 1]
for i in range( 2, size + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
H, W, A, B = map(int,input().split())
ans = 0
for i in range(W-B):
ans += cmb(H-A-1+(B+i), B+i, mod) * cmb(A-1+W-B-1-i, A-1, mod)
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s183501806 | p04046 | Accepted | def ext_euclid(a, b):
# return (x, y, gcd(a, b)) such that a * x + b * y = gcd(a, b)
if b == 0:
return 1, 0, a
y, x, v = ext_euclid(b, a % b)
y -= (a // b) * x
return x, y, v
def mod_inv(a, mod):
x, _, _ = ext_euclid(a, mod)
return x % mod
def comb_list_1(H, W, A, B, mod, modinv_list):
# (h+B-1)_C_(B-1) (h in {0, ..., H-A-1})
ret = [0 for _ in range(H - A)]
c = 1
for h in range(H - A):
ret[h] = c
c *= h + B
c *= modinv_list[h + 1]
c %= mod
return ret
def comb_list_2(H, W, A, B, mod, modinv_list):
# (-h+H+W-B-2)_C_(W-B-1) (h in {0, ..., H-A-1})
ret = [0 for _ in range(H - A)]
# initial value -> (A+W-B-1)_C_(W-B-1) (h = H-A-1)
c = 1
for a in range(1, A + 1):
c *= (a + W - B - 1)
c *= modinv_list[a]
c %= mod
# fill elements of result list from the back
for h in range(H - A - 1, -1, -1):
ret[h] = c
c *= H - h + W - B - 1
c *= modinv_list[H - h]
c %= mod
return ret
def main():
MOD = 10 ** 9 + 7
H, W, A, B = list(map(int, input().split(' ')))
modinv_list = [None] + [mod_inv(h, MOD) for h in range(1, H + 1)] # modinv doesn't exist on h = 0
combs_1 = comb_list_1(H, W, A, B, MOD, modinv_list)
combs_2 = comb_list_2(H, W, A, B, MOD, modinv_list)
ans = 0
for c1, c2 in zip(combs_1, combs_2):
ans += c1 * c2
ans %= MOD
print(ans)
if __name__ == '__main__':
main() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s759041184 | p04046 | Accepted | h, w, a, b = map(int, input().split())
mod = 10 ** 9 + 7
n = h + w
f = [1 for _ in range(n)]
f_inv = [1 for _ in range(n)]
for i in range(1, n):
f[i] = f[i-1] * i % mod
f_inv[i] = pow(f[i], mod-2, mod)
def comb(n, k):
return (f[n] * f_inv[k] % mod) * f_inv[n-k] % mod
ans = comb(h+w-2, h-1)
for i in range(b):
ans -= comb(h-a+i-1, i) * comb(a+w-i-2, a-1) % mod
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s160315145 | p04046 | Accepted | import math
#import numpy as np
import queue
from collections import deque,defaultdict
import heapq
from sys import stdin,setrecursionlimit
#from scipy.sparse.csgraph import dijkstra
#from scipy.sparse import csr_matrix
ipt = stdin.readline
setrecursionlimit(10**7)
def main():
h,w,a,b = map(int,ipt().split())
mod = 10**9+7
#nCrをmodで割った余りを求める。Nに最大値を入れて使用。
N = 2*10**5
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
def cmb(n,r,mod):
if r<0 or r>n :
return 0
r = min(r,n-r)
return g1[n]*g2[r]*g2[n-r]%mod
for i in range(2,N+1):
g1.append((g1[-1]*i)%mod)
inverse.append((-inverse[mod % i]*(mod//i))%mod)
g2.append((g2[-1]*inverse[-1])%mod)
ans = cmb(h+w-2,h-1,mod)
for i in range(max(a,b)):
ans = (ans-cmb(b+h-a-1,b-1-i,mod)*cmb(a+w-b-1,a-1-i,mod)%mod)%mod
print(ans)
return
if __name__ == '__main__':
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s660671319 | p04046 | Accepted | g1 = [1, 1]
g2 = [1, 1]
inverse = [0, 1]
MOD = 10**9+7
for i in range(2, 2*10**5+1):
g1.append((g1[-1] * i) % MOD)
inverse.append((-inverse[MOD % i] * (MOD // i)) % MOD)
g2.append((g2[-1] * inverse[-1]) % MOD)
def comb(n, r, mod=MOD):
if r < 0 or r > n:
return 0
r = min(r, n - r)
return g1[n] * g2[r] * g2[n-r] % mod
H, W, A, B = map(int, input().split())
ans = 0
n = H + W - B - 1
for i in range(1, H-A+1):
ans += comb(n-i, H-i) * comb(B+i-2, B-1) % MOD
ans %= MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s113472321 | p04046 | Accepted | # 練習
import math
h,w,a,b = list(map(int, input().split()))
p = 10**9+7
# 方針
# (0,0) ~ (0,w-1)
# (h-1,0 )~ (h-1,w-1)で考える
# 通れないのは(h-a) ~ (h-1)行かつ(0) ~ (b-1) 列のところ
# b <= i <= w-1 のiについて1,2,3の組み合わせはそれぞれ以下の通り
# 1, (0,0) ~ (h-a-1,i) (h-a-1+i)! /(h-a-1)! * i!
# 2, (h-a-1,i )~(h-a,i) 1
# 3, (h-a,i) ~ (h-1,w-1) (a-1+w-1-i)! /(a-1)! * (w-1-i)!
def cmb(n, k, mod, fac, ifac):
"""
nCkを計算する
"""
k = min(k, n-k)
return fac[n] * ifac[k] * ifac[n-k] % mod
def make_tables(mod, n):
"""
階乗テーブル、逆元の階乗テーブルを作成する
"""
fac = [1, 1] # 階乗テーブル・・・(1)
ifac = [1, 1] #逆元の階乗テーブル・・・(2)
inverse = [0, 1] #逆元テーブル・・・(3)
for i in range(2, n+1):
fac.append((fac[-1] * i) % mod)
inverse.append((-inverse[mod % i] * (mod//i)) % mod)
ifac.append((ifac[-1] * inverse[-1]) % mod)
return fac, ifac
fac, ifac = make_tables(p, h+w-2)
total = 0
for i in range(b, w):
r1 = cmb(h-a-1+i,i,p,fac, ifac)
r3 = cmb(a-1+w-1-i, a-1,p,fac, ifac)
total = total +( r1*r3)
print(total%p) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s616725498 | p04046 | Accepted | MOD=10**9+7
H,W,A,B=map(int,input().split())
def invmod(a):
return pow(a,MOD-2,MOD)
def comb_mod(n,r):
if 0<=r<=n:
return fact_dic[n]*fact_inv_dic[r]*fact_inv_dic[n-r]
else:
return 0
fact_dic={0:1}
fact_inv_dic={0:1}
fact_mod=1
for i in range(1,H+W-1):
fact_mod=(fact_mod*i)%MOD
fact_dic[i]=fact_mod
fact_inv_dic[i]=invmod(fact_mod)
answer=0
for i in range(B,W):
answer+=comb_mod(H-A-1+i,i)*comb_mod(A-1+W-1-i,W-1-i)
answer%=MOD
print(answer) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s302106136 | p04046 | Accepted | MOD=10**9+7
H,W,A,B=map(int,input().split())
def invmod(a):
return pow(a,MOD-2,MOD)
def comb_mod(n,r):
if 0<=r<=n:
return fact_dic[n]*fact_inv_dic[r]*fact_inv_dic[n-r]
else:
return 0
fact_dic={0:1}
fact_inv_dic={0:1}
fact_mod=1
for i in range(1,H+W-1):
fact_mod=(fact_mod*i)%MOD
fact_dic[i]=fact_mod
fact_inv_dic[i]=invmod(fact_mod)
answer=0
for i in range(B,W):
answer+=comb_mod(H-A+B-1,i)*comb_mod(W+A-B-1,W-1-i)
answer%=MOD
print(answer) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s189114842 | p04046 | Accepted | MOD=10**9+7
H,W,A,B=map(int,input().split())
def invmod(a):
return pow(a,MOD-2,MOD)
def comb_mod(n,r):
return fact_dic[n]*fact_inv_dic[r]*fact_inv_dic[n-r]
fact_dic={0:1}
fact_inv_dic={0:1}
fact_mod=1
for i in range(1,H+W-1):
fact_mod=(fact_mod*i)%MOD
fact_dic[i]=fact_mod
fact_inv_dic[i]=invmod(fact_mod)
answer=0
if H-A>=W-B:
for i in range(B,W):
answer+=comb_mod(H-A+B-1,i)*comb_mod(W+A-B-1,W-1-i)
answer%=MOD
else:
for j in range(H-A):
answer+=comb_mod(H-A+B-1,B+j)*comb_mod(W+A-B-1,W-B-1-j)
answer%=MOD
print(answer) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s351728424 | p04046 | Accepted | import math
p=1000000007
g1=[1,1]
g2=[1,1]
inverse=[0,1]
for i in range(2,2*(10**5)+1):
g1.append((g1[-1]*i)%p)
inverse.append((-inverse[p%i]*(p//i))%p)
g2.append((g2[-1]*inverse[-1])%p)
def cmb2(n, r, mod):
if (r<0 or r>n):return 0
r = min(r,n-r)
return g1[n]*g2[r]*g2[n-r]%mod
def chwp(h,w,p):
if h==1 or w==1:return 1
else:return cmb2(h+w-2,h-1,p)
h,w,a,b= map(int,input().split())
ans=0
for i in range(1,h-a+1):ans=(ans+chwp(i,b,p)*chwp(h-i+1,w-b,p))%p
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s629168942 | p04046 | Accepted | h,w,a,b = map(int,input().split())
mod = 10**9+7
fact = [1,1]
finv = [1,1]
inv = [0,1]
for i in range(2,h+w+5):
fact.append((fact[-1]*i)%mod)
inv.append((inv[mod%i]*(mod-mod//i))%mod)
finv.append((finv[-1]*inv[-1])%mod)
def nCr(n,r,mod):
if r > n:
return 0
else:
return fact[n]*finv[r]*finv[n-r]%mod
ans = 0
for i in range(100000):
x = h-a-i
y = b+1+i
if 0 >= x or y > w:
break
ans += nCr(h+w-x-y,h-x,mod)*nCr(x+y-2,x-1,mod)%mod
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s016401409 | p04046 | Accepted | import sys
sys.setrecursionlimit(10000000)
MOD = 10 ** 9 + 7
INF = 10 ** 15
def main():
H,W,A,B = map(int,input().split())
MAXN = H + W + 3
factorial = [1]
for i in range(1,MAXN + 1):
factorial.append(factorial[-1]*i%MOD)
inv_factorial = [-1] * (MAXN + 1)
inv_factorial[-1] = pow(factorial[-1],MOD - 2,MOD)
for i in range(MAXN - 1,-1,-1):
inv_factorial[i] = inv_factorial[i + 1]*(i + 1)%MOD
fact = lambda N:factorial[N]
nck = lambda N,K: 0 if K > N or K < 0 else factorial[N]*inv_factorial[N - K]*inv_factorial[K]%MOD
dist = lambda sy,sx,gy,gx: nck(gy - sy + gx - sx,gy - sy)
ans = 0
if H - A < W - B:
H,W = W,H
A,B = B,A
for i in range(W - B):
x = B + i + 1
y = H - A - i
ans += dist(1,1,y,x)*dist(y,x,H,W)%MOD
ans %= MOD
print(ans)
if __name__ == '__main__':
main() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s380416209 | p04046 | Accepted | mod = 10 ** 9 + 7
N = 10 ** 6
fact = [1, 1]
factinv = [1, 1]
inv = [0, 1]
for i in range(2, N + 1):
fact.append(fact[-1] * i % mod)
inv.append((-inv[mod % i] * (mod // i)) % mod)
factinv.append((factinv[-1] * inv[-1]) % mod)
def combi_mod(n, r, p):
if (r < 0) or (n < r):
return 0
r = min(r, n - r)
return fact[n] * factinv[r] * factinv[n - r] % p
H, W, A, B = map(int, input().split())
if B < W / 2:
not_ans = 0
total = combi_mod((H - 1) + (W - 1), H-1, mod)
for i in range(B):
sq1h = H - A
sq1w = i + 1
sq2h = A
sq2w = W - i
n = combi_mod((sq1h -1) + (sq1w - 1), (sq1h -1), mod) * combi_mod((sq2h - 1) + (sq2w - 1), (sq2h - 1), mod) % mod
not_ans = (not_ans + n) % mod
ans = (total - not_ans) % mod
print(ans)
else:
ans = 0
for i in range(B, W):
sq1h = H - A
sq1w = i + 1
sq2h = A
sq2w = W - i
n = combi_mod((sq1h - 1) + (sq1w - 1), (sq1h - 1), mod) * combi_mod((sq2h - 1) + (sq2w - 1), (sq2h - 1), mod)
ans = (ans + n) % mod
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s716750790 | p04046 | Accepted | # -*- coding: utf-8 -*-
import sys
sys.setrecursionlimit(10**9)
INF=10**18
MOD=10**9+7
input=lambda: sys.stdin.readline().rstrip()
YesNo=lambda b: bool([print('Yes')] if b else print('No'))
YESNO=lambda b: bool([print('YES')] if b else print('NO'))
int1=lambda x:int(x)-1
def main():
H,W,A,B=map(int,input().split())
def COMinit(n,MOD):
fac,finv,inv=[0]*max(2,n+1),[0]*max(2,n+1),[0]*max(2,n+1)
fac[0]=fac[1]=1
finv[0]=finv[1]=1
inv[1]=1
for i in range(2,(n+1)):
fac[i]=fac[i-1]*i%MOD
inv[i]=MOD-inv[MOD%i]*(MOD//i)%MOD
finv[i]=finv[i-1]*inv[i]%MOD
return fac,finv,inv
fac,finv,inv=COMinit(H+W,MOD)
def COM(n, k, MOD=MOD):
if n<k or n<0 or k<0:
return 0
return fac[n]*(finv[k]*finv[n-k]%MOD)%MOD
ans=0
for i in range(B,W):
ans+=COM(H-A-1+i,i)*COM(A-2+W-i,A-1)
ans%=MOD
print(ans)
if __name__ == '__main__':
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s483029157 | p04046 | Accepted | H,W,A,B = map(int,input().split())
N=H+W
fact = [0]*(N+1)
ifact = [0]*(N+1)
inv = [0]*(N+1)
p=10**9+7
def combination(n):
fact[0] = 1
fact[1] = 1
ifact[0] = 1
ifact[1] = 1
inv[1] = 1
for i in range(2,n+1):
fact[i] = (fact[i-1]*i)%p
inv[i] = p - inv[p%i]*(p//i)%p
ifact[i] = (ifact[i-1]*inv[i])%p
def op(n,k):
if k<0 or k>n or n<0:
return 0
return (fact[n]*ifact[k]*ifact[n-k])%p
combination(N)
b = op(H-A+B-1, B)
res = 0
for i in range(A):
res = (res + op(W-B-2+i, i))%p
res = (res*b)%p
for i in range(H-A):
res = (res + op(B+i, i)*op(H-i-1+W-B-2,W-B-2))%p
if H-A==1 and W-B==1:
res = 1
elif H-A==1:
res = op(W-B+H-2, H-1)
elif W-B==1:
res = op(H-A+W-2, W-1)
print(res) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s820510133 | p04046 | Accepted | h,w,a,b = map(int, input().split())
import math
ans = 0
mod = 10**9+7
l =[i for i in range(1,h+w+2)]
for i in range(1,len(l)-1):
l[i+1] = l[i+1]*l[i]%mod
l = [1]+ l
gyakugen = [pow(l[i], mod-2, mod) for i in range(1, len(l))]
gyakugen = [1] + gyakugen
for p in range(1, w-b+1):
ans += l[(h-a-1+b+p-1)]*l[w-(b+p)+a-1]*\
gyakugen[h-a-1]*gyakugen[b+p-1] * gyakugen[a-1]*gyakugen[w-(b+p)]
print(int(ans)%mod) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s773831563 | p04046 | Accepted | H, W, A, B = map(int, input().split())
mod = int(1e9) + 7
def inved(a):
x, y, u, v, k, l = 1, 0, 0, 1, a, mod
while l != 0:
x, y, u, v = u, v, x - u * (k // l), y - v * (k // l)
k, l = l, k % l
return x % mod
fact = [1 for _ in range(H+W+A+B+1)]
invf = [1 for _ in range(H+W+A+B+1)]
for i in range(H+W+A+B):
fact[i+1] = (fact[i] * (i + 1)) % mod
invf[-1] = inved(fact[-1])
for i in range(H+W+A+B, 0, -1):
invf[i-1] = (invf[i] * i) % mod
S = 0
for i in range(H-A):
S += (fact[i+B-1] * invf[i] * fact[H-i+W-B-2] * invf[H-1-i]) % mod
S %= mod
S *= (invf[B-1] * invf[W-B-1]) % mod
S %= mod
print(S) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s196254093 | p04046 | Accepted | # Combination
MOD = 10**9+7
MAX = 2*10**5
fac = [1,1] + [0]*MAX
finv = [1,1] + [0]*MAX
inv = [0,1] + [0]*MAX
for i in range(2,MAX+2):
fac[i] = fac[i-1] * i % MOD
inv[i] = -inv[MOD%i] * (MOD // i) % MOD
finv[i] = finv[i-1] * inv[i] % MOD
def comb(n,r):
if n < r: return 0
if n < 0 or r < 0: return 0
return fac[n] * (finv[r] * finv[n-r] % MOD) % MOD
H, W, A, B = map(int, input().split())
ans = 0
for i in range(1, H-A+1):
cnt = comb(i-1+B-1, i-1)
#print(i, cnt)
cnt *= comb(H-i+W-B-1, H-i)
ans += cnt
ans %= MOD
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s047331751 | p04046 | Accepted | #ライブラリの点検
class Data():
def __init__(self):
self.power=1
self.rev=1
class Combi():
def __init__(self,N,mod):
self.lists=[Data() for _ in range(N+1)]
self.mod=mod
for i in range(2,N+1):
self.lists[i].power=((self.lists[i-1].power)*i)%self.mod
self.lists[N].rev=pow(self.lists[N].power,self.mod-2,self.mod)
for j in range(N,0,-1):
self.lists[j-1].rev=((self.lists[j].rev)*j)%self.mod
def combi(self,K,R):
if K<R:
return 0
else:
return ((self.lists[K].power)*(self.lists[K-R].rev)*(self.lists[R].rev))%self.mod
######################
h,w,a,b=map(int,input().split())
ans=0
mod=10**9+7
C=Combi(w+h+2,mod)
for i in range(h-a):
ans+=C.combi(b+i-1,i)*C.combi(w+h-2-b-i,h-1-i)%mod
print(ans%mod)
###################### | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s375158317 | p04046 | Accepted | #!/usr/bin/env python3
import sys
# import math
# from string import ascii_lowercase, ascii_upper_case, ascii_letters, digits, hexdigits
# import re # re.compile(pattern) => ptn obj; p.search(s), p.match(s), p.finditer(s) => match obj; p.sub(after, s)
# from operator import itemgetter # itemgetter(1), itemgetter('key')
# from collections import deque # deque class. deque(L): dq.append(x), dq.appendleft(x), dq.pop(), dq.popleft(), dq.rotate()
# from collections import defaultdict # subclass of dict. defaultdict(facroty)
# from collections import Counter # subclass of dict. Counter(iter): c.elements(), c.most_common(n), c.subtract(iter)
# from heapq import heapify, heappush, heappop # built-in list. heapify(L) changes list in-place to min-heap in O(n), heappush(heapL, x) and heappop(heapL) in O(lgn).
# from heapq import nlargest, nsmallest # nlargest(n, iter[, key]) returns k-largest-list in O(n+klgn).
# from itertools import count, cycle, repeat # count(start[,step]), cycle(iter), repeat(elm[,n])
# from itertools import groupby # [(k, list(g)) for k, g in groupby('000112')] returns [('0',['0','0','0']), ('1',['1','1']), ('2',['2'])]
# from itertools import starmap # starmap(pow, [[2,5], [3,2]]) returns [32, 9]
# from itertools import product, permutations # product(iter, repeat=n), permutations(iter[,r])
# from itertools import combinations, combinations_with_replacement
# from itertools import accumulate # accumulate(iter[, f])
# from functools import reduce # reduce(f, iter[, init])
# from functools import lru_cache # @lrucache ...arguments of functions should be able to be keys of dict (e.g. list is not allowed)
# from bisect import bisect_left, bisect_right # bisect_left(a, x, lo=0, hi=len(a)) returns i such that all(val<x for val in a[lo:i]) and all(val>-=x for val in a[i:hi]).
# from copy import deepcopy # to copy multi-dimentional matrix without reference
# from fractions import gcd # for Python 3.4 (previous contest @AtCoder)
def main():
mod = 1000000007 # 10^9+7
inf = float('inf') # sys.float_info.max = 1.79...e+308
# inf = 2 ** 64 - 1 # (for fast JIT compile in PyPy) 1.84...e+19
sys.setrecursionlimit(10**6) # 1000 -> 1000000
def input(): return sys.stdin.readline().rstrip()
def ii(): return int(input())
def mi(): return map(int, input().split())
def mi_0(): return map(lambda x: int(x)-1, input().split())
def lmi(): return list(map(int, input().split()))
def lmi_0(): return list(map(lambda x: int(x)-1, input().split()))
def li(): return list(input())
def make_factorial_table(size, mod):
'''
fact_mod[i] は i! % mod を表す。fact_mod[0] ~ facto_mod[size] まで計算可能なテーブルを返す
>>> make_factorial_table(20, 10**9+7)
[1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600, 227020758, 178290591, 674358851, 789741546, 425606191, 660911389, 557316307, 146326063]
'''
fact_mod = [1] * (size + 1)
for i in range(1, size + 1):
fact_mod[i] = (fact_mod[i - 1] * i) % mod
return fact_mod
def combination(n, r, mod, fact_table):
'''
フェルマーの小定理
a ^ p-1 ≡ 1 (mod p)
a ^ p-2 ≡ 1/a (mod p) (逆元)
nCr = (n!) / ((n-r)! * r!) だが、mod p の世界ではこの分母を逆元を用いて計算しておくことが可能
>>> m = 1000000007
>>> fact_table = make_factorial_table(100, m)
>>> combination(10, 5, m, fact_table)
252
>>> combination(100, 50, m, fact_table)
538992043
'''
numerator = fact_table[n]
denominator = (fact_table[n-r] * fact_table[r]) % mod
# pow はすでに繰り返し二乗法で効率的に実装されている
return (numerator * pow(denominator, mod-2, mod)) % mod
h, w, a, b = mi()
# sigma {k = b to w-1} h-1-a+kCh-1-a * a-1+w-1-kCa-1
# sample 2 だと {k=4to6} 6+kC6 * 2+6-kC2 = (10C6 * 4C2 + 11C6 * 3C2 + 12C6 * 2C2)
fact_table = make_factorial_table(2 * h + 2 * w, mod)
ans = 0
for k in range(b, w):
# print(f"{h-1-a+k} {h-1-a} / {a-1+w-1-k} {a-1}")
ans = (ans + combination(h-1-a+k, h-1-a, mod, fact_table) * combination(a-1+w-1-k, a-1, mod, fact_table)) % mod
print(ans)
if __name__ == "__main__":
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s317456342 | p04046 | Accepted | import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7
lim = 2*10**5 #必要そうな階乗の限界を入力
#階乗#
fact = [1] * (lim+1)
for n in range(1, lim+1):
fact[n] = n * fact[n-1] % mod
#階乗の逆元#
fact_inv = [1]*(lim+1)
fact_inv[lim] = pow(fact[lim], mod-2, mod)
for n in range(lim, 0, -1):
fact_inv[n-1] = n*fact_inv[n]%mod
def C(n, r):
return (fact[n]*fact_inv[r]%mod)*fact_inv[n-r]%mod
H, W, A, B = MAP()
ans = 0
for n in range(B, W):
way = C(H-A-1+n, n)*C(W-n-1+A-1, A-1)%mod
ans = (ans+way)%mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s080701961 | p04046 | Accepted | import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees, log2
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7
lim = 2*10**5 #必要そうな階乗の限界を入力
#階乗#
fact = [1] * (lim+1)
for n in range(1, lim+1):
fact[n] = n * fact[n-1] % mod
#階乗の逆元#
fact_inv = [1]*(lim+1)
fact_inv[lim] = pow(fact[lim], mod-2, mod)
for n in range(lim, 0, -1):
fact_inv[n-1] = n*fact_inv[n]%mod
def C(n, r):
return (fact[n]*fact_inv[r]%mod)*fact_inv[n-r]%mod
H, W, A, B = MAP()
ans = 0
for n in range(B, W):
way = C(H-A-1+n, n)*C(W-n-1+A-1, A-1)%mod
ans = (ans+way)%mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s973821399 | p04046 | Accepted | import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees, log2
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7
lim = 2*10**5 #必要そうな階乗の限界を入力
#階乗#
fact = [1] * (lim+1)
for n in range(1, lim+1):
fact[n] = n * fact[n-1] % mod
#階乗の逆元#
fact_inv = [1]*(lim+1)
fact_inv[lim] = pow(fact[lim], mod-2, mod)
for n in range(lim, 0, -1):
fact_inv[n-1] = n*fact_inv[n]%mod
def C(n, r):
return (fact[n]*fact_inv[r]%mod)*fact_inv[n-r]%mod
H, W, A, B = MAP()
ans = 0
for n in range(B, W):
way = C(H-A-1+n, n)*C(W-n-1+A-1, A-1)%mod
ans = (ans+way)%mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s239755774 | p04046 | Accepted | import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees, log2
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7
lim = 2*10**6
fact = [1]*(lim+1)
for n in range(1, lim+1):
fact[n] = n*fact[n-1]%mod
fact_inv = [1]*(lim+1)
fact_inv[lim] = pow(fact[lim], mod-2, mod)
for n in range(lim, 0, -1):
fact_inv[n-1] = n*fact_inv[n]%mod
def C(n, r):
return (fact[n]*fact_inv[r]%mod)*fact_inv[n-r]%mod
H, W, A, B = MAP()
ans = 0
for n in range(B, W):
way = C(H-A-1+n, n)*C(W-n-1+A-1, A-1)%mod
ans = (ans+way)%mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s529214189 | p04046 | Accepted | def combmod_pre(N, p):
'''
sample usage:
p = 10**9+7
N = 10**6
fact, finv = combmod_pre(N, p)
combmod(n, r, p)
'''
fact = [1, 1]
finv = [1, 1]
inv = [0, 1]
for i in range(2, N+1):
fact.append((fact[-1] * i) % p)
inv.append((-inv[p % i] * (p // i)) % p)
finv.append((finv[-1] * inv[-1]) % p)
return (fact, finv)
def combmod(n, r, fact, finv, p):
'''
sample usage:
combmod(3000, 1000, fact, finv, p)
p is a same value of combmod_pre's argument
fact, finv is return value of combmod_pre
'''
if r < 0 or n < r:
return 0
return fact[n] * finv[r] * finv[n-r] % p
p = 10**9+7
N = 10**6
fact, finv = combmod_pre(N, p)
h, w, a, b = (int(x) for x in input().split())
ans = 0
for j in range(b, w):
x = combmod(h - a - 1 + j, j, fact, finv, p)
y = combmod(a + w - 2 - j, w-1 - j, fact, finv, p)
ans += x * y
print(ans % p)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s194170678 | p04046 | Accepted | def combmod(n, r, p):
if r < 0 or n < r:
return 0
return fact[n] * finv[r] * finv[n-r] % p
p = 10**9+7
N = 10**6
fact = [1, 1]
finv = [1, 1]
inv = [0, 1]
for i in range(2, N+1):
fact.append((fact[-1] * i) % p)
inv.append((-inv[p % i] * (p // i)) % p)
finv.append((finv[-1] * inv[-1]) % p)
h, w, a, b = (int(x) for x in input().split())
ans = 0
for j in range(b, w):
ans += combmod(h-a-1 + j, j, p) * combmod(a+w-2 - j, w-1 - j, p)
print(ans % p)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s067452857 | p04046 | Accepted | MOD = 10**9+7
h,w,a,b = map(int,input().split())
n = h+w
fac = [1]*(n+1)
fac_inv = [0]*(n+1)
for i in range(n):
fac[i+1] = (fac[i] * (i+1)) %MOD
fac_inv[-1] = pow(fac[-1],MOD-2,MOD)
for i in range(n,0,-1):
fac_inv[i-1] = (fac_inv[i] * i) % MOD
def comb(n,k):
if k<0 or k>n:
return 0
x = (fac[n] * (fac_inv[k] * fac_inv[n-k])%MOD)%MOD
return x
ans = 0
for i in range(w-b):
ans += comb((h-a-1) + b+i, b+i) * comb((a-1) + (w - b-i-1), a-1) %MOD
ans %= MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s292934544 | p04046 | Accepted | def cmb(n, r, mod):#コンビネーションの高速計算
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
mod = 10**9+7 #出力の制限
N = 2*10**5
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
for i in range( 2, N + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
H,W,A,B=map(int,input().split())
ans=cmb(H+W-2,H-1,mod)
for i in range(H-A,H):
ans-=cmb(i+B-1,B-1,mod)*cmb(H+W-2-i-B,W-B-1,mod)
ans%=mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s633679559 | p04046 | Accepted | import sys
def comb(n, r, mod=None):
if r == 0 or r == n:
return 1
r = min([r, n-r])
x, y = 1, 1
ans = 1
for i in range(1, r+1):
if mod:
x *= n+1-i
y *= i
x %= mod
y %= mod
else:
ans *= n+1-i
ans //= i
ans = x*pow(y, mod-2, mod)%mod if mod else ans
return ans
def main():
input = sys.stdin.readline
h, w, a, b = map(int, input().split())
mod = pow(10, 9)+7
bef, aft = 1, comb(h+w-b-2, h-1, mod)
ans = 0
for i in range(h-a):
ans += bef*aft
ans %= mod
bef = bef*(i+b)*pow(i+1, mod-2, mod)%mod
aft = aft*(h-i-1)*pow(h-i+w-b-2, mod-2, mod)%mod
print(ans)
if __name__ == "__main__":
main() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s586146267 | p04046 | Accepted | MOD=10**9+7
UPPERLIMIT=2*(10**5)+1
MODMUL=[1, 1]+[0]*(UPPERLIMIT-1)
for i in range(2, UPPERLIMIT+1):
MODMUL[i]=MODMUL[i-1]*i%MOD
MODDIV=[1]*UPPERLIMIT+[pow(MODMUL[-1], MOD-2, MOD)]
for i in range(UPPERLIMIT, 0, -1):
MODDIV[i-1]=MODDIV[i]*i%MOD
H, W, A, B=map(int, input().split())
ans=(((MODMUL[H+W-2]*MODDIV[H-1])%MOD)*MODDIV[W-1])%MOD
x=[MODMUL[H-A+B+i-1]*MODDIV[B-1]*MODDIV[H-A+i]%MOD for i in range(A)]
y=[MODMUL[W+A-B-i-1]*MODDIV[W-B]*MODDIV[A-i-1]%MOD for i in range(A)]
for i in range(A-1, 0, -1):
x[i]-=x[i-1]
for i in range(A):
ans-=(x[i]*y[i]%MOD)
ans%=MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s236037854 | p04046 | Accepted | H, W, A, B = map(int, input().split())
MAX = 2 * 10 ** 5 + 1
MOD = 10 ** 9 + 7
# Factorial
fac = [0] * (MAX + 1)
fac[0] = 1
fac[1] = 1
for i in range(2, MAX + 1):
fac[i] = fac[i - 1] * i % MOD
# Inverse factorial
finv = [0] * (MAX + 1)
finv[MAX] = pow(fac[MAX], MOD - 2, MOD)
for i in reversed(range(1, MAX + 1)):
finv[i - 1] = finv[i] * i % MOD
def comb(a, b):
return fac[a + b] * finv[a] * finv[b]
ans = 0
for i in range(B, W):
ans += comb(i, H - A - 1) * comb(W - i - 1, A - 1) % MOD
ans %= MOD
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s469473134 | p04046 | Accepted |
a,b,c,d = list(map(int, input().split()))
def cmb(n, r, p):
if (r < 0) or (n < r):
return 0
r = min(r, n - r)
return fact[n] * factinv[r] * factinv[n-r] % p
p = 10**9+7
N = 10 ** 6 + 2
fact = [1, 1] # fact[n] = (n! mod p)
factinv = [1, 1] # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1] # factinv 計算用
for i in range(2, N + 1):
fact.append((fact[-1] * i) % p)
inv.append((-inv[p % i] * (p // i)) % p)
factinv.append((factinv[-1] * inv[-1]) % p)
def wh(w,h):
return cmb(w+h,w,10**9+7)
ans = wh(b-1,a-1)
#print(ans)
for i in range(d):
tmp = wh(i,a-c-1) * wh(c-1,b-i-1) % p
ans += p
ans -= tmp
ans %= p
#print(ans)
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s840046869 | p04046 | Accepted | MOD = 10 ** 9 + 7
def prepare(n):
global MOD
modFacts = [0] * (n + 1)
modFacts[0] = 1
for i in range(n):
modFacts[i + 1] = (modFacts[i] * (i + 1)) % MOD
invs = [1] * (n + 1)
invs[n] = pow(modFacts[n], MOD - 2, MOD)
for i in range(n, 1, -1):
invs[i - 1] = (invs[i] * i) % MOD
return modFacts, invs
def pathVar(sx, sy, gx, gy):
x = gx - sx
y = gy - sy
rst = modFacts[x + y]
rst *= invs[x] * invs[y]
rst %= MOD
return rst
H, W, A, B = map(int, input().split())
# H -= 1; W -= 1
modFacts, invs = prepare(H + W)
cnt = 0
while A > 0 and B > 0:
x = H - A
y = B - 1
path1 = pathVar(0, 0, x, y)
path2 = pathVar(x, y, H - 1, W - 1)
cnt += path1 * path2
cnt %= MOD
A -= 1; B -= 1
ans = pathVar(0, 0, H - 1, W - 1)
print((ans - cnt) % MOD)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s925317109 | p04046 | Accepted | #coding: utf-8
import math
import heapq
import bisect
import numpy as np
from collections import Counter, deque
import itertools
#from scipy.misc import comb
MOD = 10**9+7
H,W,A,B = map(int,input().split())
def comb(a,b):
p = fac[a-b]*fac[b]%MOD
return fac[a]*pow(p,MOD-2,MOD)%MOD
fac=[1]
for i in range(H+W):
fac.append(fac[-1]*(i+1)%MOD)
ans=0
for i in range(W-B):
p = comb(H-A-1+B+i,B+i)*comb(W-B-i-2+A,A-1)
ans += p%MOD
ans %= MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s791598446 | p04046 | Accepted | h,w,a,b=map(int,input().split())
inv=[0]*(2*max(h,w)+1)
fact=[0]*(2*max(h,w)+1)
inv[0]=1;fact[0]=1
mod=10**9+7
for i in range(1,2*max(h,w)+1):
fact[i]=fact[i-1]*i%mod
inv[-1]=pow(fact[-1],mod-2,mod)
for i in range(2*max(h,w),0,-1):
inv[i-1]=inv[i]*i%mod
ans=0
for yoko in range(b+1,w+1):
re=fact[yoko-1+h-1-a]*inv[h-1-a]*inv[yoko-1]%mod
rr=fact[w-yoko+a-1]*inv[w-yoko]*inv[a-1]%mod
ans=(ans+re*rr%mod)%mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s810498265 | p04046 | Accepted | H, W, A, B = [int(_) for _ in input().split()]
mod = 10**9 + 7
X = [i for i in range(H + W + 1)]
X[0] = 1
for i in range(2, H + W + 1):
X[i] = X[i - 1] * i % mod
Y = X.copy()
Y[-1] = pow(Y[-1], mod - 2, mod)
for i in range(H + W, 1, -1):
Y[i - 1] = i * Y[i] % mod
def comb(x, y):
return X[x] * Y[y] * Y[x - y] % mod
ans = 0
for i in range(B, min(B + H - A, W)):
ans += comb(H - A + B - 1, i) * comb(W + A - B - 1, W - i - 1)
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s693966858 | p04046 | Accepted | U = 2*10**5
MOD = 10**9+7
fact = [1] * (U+1)
fact_inv = [1] * (U+1)
# 階乗のテーブル作成
for i in range(1, U+1):
fact[i] = (fact[i-1] * i) % MOD
# 階乗の逆元のテーブル作成
fact_inv[U] = pow(fact[U], MOD-2, MOD)
for i in range(U, 0, -1):
fact_inv[i-1] = (fact_inv[i] * i) % MOD
def comb(n, k):
if k < 0 or k > n:
return 0
x = fact[n]
x *= fact_inv[k]
x %= MOD
x *= fact_inv[n-k]
x %= MOD
return x
H, W, A, B = [int(i) for i in input().split(" ")]
ans = 0
# 経路の足し上げ C(縦+横, 縦(or横)) (重複のある組み合わせ)
for i in range(B, W):
ans += comb((H-A-1) + i, i) * comb((A - 1) + (W-1-i), W-1- i) % MOD
ans %= MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s033787017 | p04046 | Accepted | def prepare(n, MOD):
f = 1
factorials = [1]
for m in range(1, n + 1):
f *= m
f %= MOD
factorials.append(f)
inv = pow(f, MOD - 2, MOD)
invs = [1] * (n + 1)
invs[n] = inv
for m in range(n, 1, -1):
inv *= m
inv %= MOD
invs[m - 1] = inv
return factorials, invs
h, w, a, b = map(int, input().split())
MOD = 10 ** 9 + 7
facts, invs = prepare(h + w, MOD)
ans = 0
ib = invs[b - 1]
iwb = invs[w - b - 1]
for down in range(h - a):
left_pattern = facts[b - 1 + down] * ib * invs[down] % MOD
right_pattern = facts[h - 1 - down + w - b - 1] * invs[h - 1 - down] * iwb % MOD
ans = (ans + left_pattern * right_pattern) % MOD
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s932614654 | p04046 | Accepted | H, W, A, B = map(int, input().split())
mod = 10**9 + 7
fact = [1] * (H+W+1)
fact_inv = [1] * (H+W+1)
for i in range(1, H+W+1):
fact[i] = i * fact[i-1] % mod
fact_inv[H+W] = pow(fact[H+W], mod-2, mod)
for i in range(1, H+W+1)[::-1]:
fact_inv[i-1] = i * fact_inv[i] % mod
comb = lambda n, k: fact[n] * fact_inv[k] * fact_inv[n-k] % mod
ans = 0
for i in range(B+1, W+1):
ans += comb((i-1) + (H-A-1), i-1) * comb((W-i) + (A-1), W-i) % mod
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s418523274 | p04046 | Accepted | mod = 10 ** 9 + 7
fac_table = [1 for i in range(200001)]
inv_table = [1 for i in range(200001)]
def make_table(h, w):
for i in range(1, h + w - 1):
fac_table[i] = fac_table[i - 1] * i % mod
inv_table[i] = pow(fac_table[i], mod - 2, mod)
def comb(n, r):
return fac_table[n] * inv_table[n - r] % mod * inv_table[r] % mod
def resolve():
H, W, A, B = map(int, input().split())
make_table(H, W)
print(
sum(
[
comb(H - A - 1 + i, i) * comb(A - 1 + W - i - 1, A - 1) % mod
for i in range(B, W)
]
)
% mod
)
if __name__ == "__main__":
resolve() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s257839064 | p04046 | Accepted | H, W, A, B = map(int, input().split())
mod = 10**9 + 7
U = 2 * 10**5
factorial = [1 for _ in range(U + 1)]
for i in range(1, U + 1):
factorial[i] = (factorial[i - 1] * i) % mod
inverse = [1 for _ in range(U + 1)]
inverse[U] = pow(factorial[U], mod - 2, mod)
for i in range(U, 0, -1):
inverse[i - 1] = (inverse[i] * i) % mod
def comb(n, k):
if k < 0 or k > n:
return 0
x = factorial[n]
x *= inverse[k]
x %= mod
x *= inverse[n - k]
x %= mod
return x
ans = 0
for i in range(H - A):
x = comb(B - 1 + i, i)
a = H - 1 - i
b = W - 1 - B
x *= comb(a + b, a)
x %= mod
ans += x
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s456454409 | p04046 | Accepted | import math
import time
DIV_VALUE = 10**9 + 7
def calcModOfPow(a, n, p):
btm = a
ans = 1
while n != 0:
# print('btm: {}'.format(btm))
if n & 1:
ans = (ans * btm) % p
# print('ans: {}'.format(ans))
n = n>>1
btm = (btm**2) % p
# print(n)
return ans
def calcModOfInv(a, p):
b = p
x = 1
y = 0
while b:
div = a // b
a -= div * b
[a, b] = [b, a]
x -= div * y
[x, y] = [y, x]
x %= p
if x < 0:
x += p
return x
class FirstHalf:
def __init__(self, H, W, A, B):
self.H = H
self.W = W
self.A = A
self.B = B
self.k = 0
self.div = 0
self.sup = 0
self.numOfCases = 1
def getNumOfCases(self):
if self.k != 0:
self.numOfCases = self.numOfCases * (
(self.B + self.k - 1)
) * (
calcModOfInv(self.k, DIV_VALUE)
) % DIV_VALUE
self.k += 1
# print('----- k == {} -----'.format(self.k))
# print(self.numOfCases)
# self.numOfCases %= DIV_VALUE
return self.numOfCases
# return self.numOfCases % DIV_VALUE
class SecondHalf:
def __init__(self, H, W, A, B):
self.H = H
self.W = W
self.A = A
self.B = B
self.k = 0
self.div = 0
self.numOfCases = 1
totalval = self.H + self.W - self.B - 2
loopval = self.H - 1 if self.H < self.W - self.B else self.W - self.B - 1
for top in range(totalval, totalval - loopval, -1):
self.numOfCases *= top
self.numOfCases %= DIV_VALUE
for bottom in range(loopval, 0, -1):
self.numOfCases *= calcModOfInv(bottom, DIV_VALUE)
self.numOfCases %= DIV_VALUE
# self.numOfCases = (
# math.factorial(self.H + self.W - self.B - 2)
# ) // (
# math.factorial(self.W - self.B - 1)
# ) // (
# math.factorial(self.H - 1)
# )
def getNumOfCases(self):
if self.k != 0:
self.numOfCases = self.numOfCases * (
self.H - self.k
) * (
calcModOfInv(
self.H + self.W - self.B - self.k - 1,
DIV_VALUE
)
) % DIV_VALUE
self.k += 1
# print(self.numOfCases)
# self.numOfCases %= DIV_VALUE
return self.numOfCases
# return self.numOfCases % DIV_VALUE
if __name__ == '__main__':
[H, W, A, B] = [int(ipt) for ipt in input().split()]
start = time.time()
fstHlf = FirstHalf(H, W, A, B)
sndHlf = SecondHalf(H, W, A, B)
totalCases = 0
mid = time.time()
# print('mid: {}'.format(mid - start))
for _ in range(H - A):
totalCases += (
fstHlf.getNumOfCases() * sndHlf.getNumOfCases()
)
totalCases %= DIV_VALUE
end = time.time()
# print('end: {}'.format(end - mid))
print(totalCases)
#print('{} {} {} {}'.format(H, W, A, B))
#print(DIV_VALUE)
# for i in range(12):
# print('inv: {}'.format(calcModOfInv(i+1, 13)))
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s475829799 | p04046 | Accepted | class cmbs(object):
def __init__(self, mod):
self.mod = mod
self.g1 = [1, 1]
self.g2 = [1, 1]
inverse = [0, 1]
for i in range(2, 10 ** 6 + 1):
self.g1.append((self.g1[-1] * i) % mod)
inverse.append((-inverse[mod % i] * (mod // i)) % mod)
self.g2.append((self.g2[-1] * inverse[-1]) % mod)
def cmb(self, n, r):
if n > 10 ** 6:
return self.cmbl(n, r)
return self.cmbr(n, r)
def cmbr(self, n, r):
if r < 0 or r > n:
return 0
r = min(r, n - r)
return self.g1[n] * self.g2[r] * self.g2[n-r] % self.mod
def cmbl(self, n, r):
t = 1
r = min(r, n-r)
for i in range(n - r + 1, n + 1):
t = t * i % self.mod
return t * self.g2[r] % self.mod
def main():
H, W, A, B = map(int, input().split())
mod = 10**9 + 7
c = cmbs(mod)
r = c.cmb(H+W-2, H-1)
for i in range(1, B+1):
r -= c.cmb(H-A+i-2, i-1) * c.cmb(A-1+W-i, A-1)
return r % mod
print(main())
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s805821572 | p04046 | Accepted | class nCrMod():
def __init__(self, mod):
self.mod = mod
self.fac = [1, 1]
self.finv = [1, 1]
self.inv = [0, 1]
def prep(self, n):
mod = self.mod
f, fi = self.fac[-1], self.finv[-1]
for i in range(len(self.fac), n + 1):
fn = f * i % mod
v = -self.inv[mod % i] * (mod // i) % mod
fin = fi * v % mod
f, fi = fn, fin
self.fac.append(f)
self.finv.append(fi)
self.inv.append(v)
def __call__(self, n, r):
if len(self.fac) <= n:
self.prep(n)
return self.fac[n] * self.finv[r] * self.finv[n - r] % self.mod
def main():
H, W, A, B = map(int, input().split())
mod = 10 ** 9 + 7
nCr = nCrMod(mod)
r = 0
a = H - A - 1
for i in range(B, W):
r = (r + nCr(a + i, i) * nCr(A - 1 + W - i - 1, W - i - 1)) % mod
return r
print(main())
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s298845173 | p04046 | Accepted | class CombinationFermat:
def __init__(self):
"""O(MAX)で前計算しておく→以降comb(a,b)はO(1)で取得可能
"""
MOD = 10**9 + 7
MAX = 2*10**5
self.fac = [0]*MAX # self.fac[n]: (n!) mod p
self.finv = [0]*MAX # self.finv[n]: (n!)^-1 mod p
self.inv = [0]*MAX # inv[n]: (n)^-1 mod -p
self.fac[0] = self.fac[1] = 1
self.finv[0] = self.finv[1] = 1
self.inv[1] = 1
for i in range(2, MAX):
self.fac[i] = self.fac[i-1] * i % MOD
self.inv[i] = MOD - self.inv[MOD % i] * (MOD//i) % MOD
self.finv[i] = self.finv[i-1] * self.inv[i] % MOD
def comb(self, n: int, r: int) -> int:
MOD = 10**9 + 7
if n < r:
return 0
if n < 0 or r < 0:
return 0
return self.fac[n] * (self.finv[r] * self.finv[n-r] % MOD) % MOD
H, W, A, B = map(int, input().split())
c = CombinationFermat()
ans = 0
MOD = 10**9 + 7
for i in range(H-A):
x = c.comb(B-1+i, i)
a = H-1-i
b = W-1-B
x *= c.comb(a+b, a)
x %= MOD
ans += x
ans %= MOD
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s876810494 | p04046 | Accepted | MOD = 10**9 + 7
MAX = 2*10**5
fac = [0]*MAX # fac[n]: (n!) mod p
finv = [0]*MAX # finv[n]: (n!)^-1 mod p
inv = [0]*MAX # inv[n]: (n)^-1 mod -p
def comb_init():
global fac, finv, inv
fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, MAX):
fac[i] = fac[i-1] * i % MOD
inv[i] = MOD - inv[MOD % i] * (MOD//i) % MOD
finv[i] = finv[i-1] * inv[i] % MOD
def comb(n: int, r: int) -> int:
global fac, finv
if n < r:
return 0
if n < 0 or r < 0:
return 0
return fac[n] * (finv[r] * finv[n-r] % MOD) % MOD
H, W, A, B = map(int, input().split())
comb_init()
ans = 0
for i in range(H-A):
x = comb(B-1+i, i)
a = H-1-i
b = W-1-B
x *= comb(a+b, a)
x %= MOD
ans += x
ans %= MOD
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s587846681 | p04046 | Accepted | class Calc:
def __init__(self, max_value, mod):
"""combination(max_value, all)"""
fact = [-1] * (max_value + 1)
fact[0] = 1
fact[1] = 1
for x in range(2, max_value + 1):
fact[x] = x * fact[x - 1] % mod
invs = [1] * (max_value + 1)
invs[max_value] = pow(fact[max_value], mod - 2, mod)
for x in range(max_value - 1, 0, -1):
invs[x] = invs[x + 1] * (x + 1) % mod
self.fact = fact
self.invs = invs
self.mod = mod
def combination(self, n, r):
if n - r < r:
return self.combination(n, n - r)
if r < 0:
return 0
if r == 0:
return 1
if r == 1:
return n
return self.fact[n] * self.invs[r] * self.invs[n - r] % self.mod
def main():
MOD = 10 ** 9 + 7
H, W, A, B = map(int, input().split())
calc = Calc(max_value=H + W, mod=MOD)
ans = 0
for x in range(B, W):
v = calc.combination(n=(H - A - 1) + x, r=x)
u = calc.combination(n=(A - 1) + (W - 1 - x), r=A - 1)
# (H-1)-(H-A)+(W-1)-x
ans = (ans + v * u) % MOD
print(ans)
if __name__ == '__main__':
main()
# import sys
#
# sys.setrecursionlimit(10 ** 7)
#
# input = sys.stdin.readline
# rstrip()
# int(input())
# map(int, input().split())
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s810428530 | p04046 | Accepted | # -*- coding: utf-8 -*-
#コンビネーション
def cmb(n, r):
if (r < 0) or (n < r):
return 0
r = min(r, n - r)
return fact[n] * factinv[r] * factinv[n-r] % mod
N = 2 * 10 ** 5 + 1000 # N は必要分だけ用意する
mod = pow(10, 9) + 7
fact = [1, 1] # fact[n] = (n! mod p)
factinv = [1, 1] # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1] # factinv 計算用
for i in range(2, N + 1):
fact.append((fact[-1] * i) % mod)
inv.append((-inv[mod % i] * (mod // i)) % mod)
factinv.append((factinv[-1] * inv[-1]) % mod)
ans = 0
h, w, a, b = map(int,input().split())
for i in range(h - a):
#print(b - 1 + i, i, w - b - 1 + h - i - 1, w - b - 1)
ans += (cmb(b - 1 + i, i) * cmb(w - b - 1 + h - i - 1, w - b - 1)) % (10 ** 9 + 7)
print(ans % (10 ** 9 + 7))
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s475392102 | p04046 | Accepted | def main():
def cmb(n, r, mod):
if (r < 0 or r > n):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
mod = 10**9+7 # 出力の制限
N = 10**6
g1 = [1, 1] # 元テーブル
g2 = [1, 1] # 逆元テーブル
inverse = [0, 1] # 逆元テーブル計算用テーブル
for i in range(2, N + 1):
g1.append((g1[-1] * i) % mod)
inverse.append((-inverse[mod % i] * (mod//i)) % mod)
g2.append((g2[-1] * inverse[-1]) % mod)
H, W, A, B = map(int, input().split())
ans = cmb((H+W-2), min(H, W)-1, mod)
tmp = 0
for i in range(B):
t = cmb(H-A-1+i, i, mod)
t *= cmb(W-1-i + A - 1, A-1, mod)
tmp += t
tmp %= mod
print((ans - tmp) % mod)
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s206436338 | p04046 | Accepted | from itertools import permutations
import sys
sys.setrecursionlimit(10 ** 6)
from bisect import *
from collections import *
from heapq import *
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def SI(): return sys.stdin.readline()[:-1]
def LLI(rows_number): return [LI() for _ in range(rows_number)]
int1 = lambda x: int(x) - 1
def MI1(): return map(int1, sys.stdin.readline().split())
def LI1(): return list(map(int1, sys.stdin.readline().split()))
p2D = lambda x: print(*x, sep="\n")
dij = [(1, 0), (0, 1), (-1, 0), (0, -1)]
# grobalにmdを設定すること
class mint:
def __init__(self, x):
self.__x = x % md
def __str__(self):
return str(self.__x)
def __neg__(self):
return mint(-self.__x)
def __add__(self, other):
if isinstance(other, mint): other = other.__x
return mint(self.__x + other)
def __sub__(self, other):
if isinstance(other, mint): other = other.__x
return mint(self.__x - other)
def __rsub__(self, other):
return mint(other - self.__x)
def __mul__(self, other):
if isinstance(other, mint): other = other.__x
return mint(self.__x * other)
__radd__ = __add__
__rmul__ = __mul__
def __truediv__(self, other):
if isinstance(other, mint): other = other.__x
return mint(self.__x * pow(other, md - 2, md))
def __rtruediv__(self, other):
return mint(other * pow(self.__x, md - 2, md))
def __pow__(self, power, modulo=None):
return mint(pow(self.__x, power, md))
md = 10**9+7
def nCr(com_n, com_r):
if com_n < com_r: return 0
return fac[com_n] * ifac[com_r] * ifac[com_n - com_r]
n_max = 200005
fac = [mint(1)]
for i in range(1, n_max + 1): fac.append(fac[-1] * i)
ifac = [mint(1)] * (n_max + 1)
ifac[n_max] /= fac[n_max]
for i in range(n_max - 1, 1, -1): ifac[i] = ifac[i + 1] * (i + 1)
def main():
h,w,a,b=MI()
cc=[]
for i in range(h-a):
cc.append(nCr(b+i,i))
#print(*cc)
ans=mint(0)
pc=0
for i,c in enumerate(cc):
ans+=(c-pc)*nCr(h-1-i+w-1-b,w-1-b)
pc=c
print(ans)
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s691061124 | p04046 | Accepted | def cmb1(n,r,mod):
if (r<0 or r>n):
return 0
r = min(r,n-r)
return g1[n]*g2[r]*g2[n-r]%mod
h,w,a,b=map(int,input().split())
# 前処理
mod=10**9+7 #出力の制限
n=10**6
g1=[1,1] # 元テーブル
g2=[1,1] # 逆元テーブル
inverse=[0,1] #逆元テーブル計算用テーブル
for i in range(2,n+1):
g1.append((g1[-1]*i)%mod)
inverse.append((-inverse[mod%i]*(mod//i))%mod)
g2.append((g2[-1]*inverse[-1])%mod)
ans=0
for i in range(b,w):
ans+=cmb1(h-a-1+i,i,mod)*cmb1(a-1+w-1-i,a-1,mod)
ans%=mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s004713854 | p04046 | Accepted | class Combination:
def __init__(self, size, mod=10**9 + 7):
self.size = size + 2
self.mod = mod
self.fact = [1, 1] + [0] * size
self.factInv = [1, 1] + [0] * size
self.inv = [0, 1] + [0] * size
for i in range(2, self.size):
self.fact[i] = self.fact[i - 1] * i % self.mod
self.inv[i] = -self.inv[self.mod % i] * (self.mod // i) % self.mod
self.factInv[i] = self.factInv[i - 1] * self.inv[i] % self.mod
def npr(self, n, r):
if n < r or n < 0 or r < 0:
return 0
return self.fact[n] * self.factInv[n - r] % self.mod
def ncr(self, n, r):
if n < r or n < 0 or r < 0:
return 0
return self.fact[n] * (self.factInv[r] * self.factInv[n - r] % self.mod) % self.mod
def nhr(self, n, r): # 重複組合せ
return self.ncr(n + r - 1, n - 1)
def factN(self, n):
if n < 0:
return 0
return self.fact[n]
H, W, A, B = map(int, input().split())
comb = Combination(H + W + 100)
MOD = 10**9 + 7
ans = 0
for w in range(B + 1, W + 1):
ans += comb.ncr(H - A + w - 2, w - 1) * comb.ncr(A + W - w - 1, A - 1)
print(ans % MOD)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s336401635 | p04046 | Accepted | import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians, acos, atan, asin, log, log10
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from fractions import gcd
def debug(*args):
if debugmode:
print(*args)
def input(): return sys.stdin.readline().strip()
def STR(): return input()
def INT(): return int(input())
def FLOAT(): return float(input())
def MAP(): return map(int, input().split())
def S_MAP(): return map(str, input().split())
def LIST(): return list(map(int, input().split()))
def S_LIST(): return list(map(str, input().split()))
def lcm(a, b): return a * b // gcd(a, b)
sys.setrecursionlimit(10 ** 9)
inf = sys.maxsize
mod = 10 ** 9 + 7
dx = [0, 0, 1, -1, 1, -1, -1, 1]
dy = [1, -1, 0, 0, 1, -1, 1, -1]
debugmode = False
#コンビネーション
def cmb(n, r):
if (r < 0) or (n < r):
return 0
r = min(r, n - r)
return fact[n] * factinv[r] * factinv[n-r] % mod
N = 2 * 10 ** 5 + 100 # N は必要分だけ用意する
fact = [1, 1] # fact[n] = (n! mod p)
factinv = [1, 1] # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1] # factinv 計算用
for i in range(2, N + 1):
fact.append((fact[-1] * i) % mod)
inv.append((-inv[mod % i] * (mod // i)) % mod)
factinv.append((factinv[-1] * inv[-1]) % mod)
h, w, a, b = MAP()
ans = 0
for i in range(1, h - a + 1):
debug(i, b + i - 2, i - 1, w - b + h - i - 1, h - i)
debug(cmb(b + i - 2, i - 1), cmb(w - b + h - i - 1, h - i))
ans += cmb(b + i - 2, i - 1) * cmb(w - b + h - i - 1, h - i) % mod
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s194116611 | p04046 | Accepted | #!usr/bin/env python3
from collections import defaultdict, deque
from heapq import heappush, heappop
from itertools import permutations, accumulate
import sys
import math
import bisect
def LI(): return [int(x) for x in sys.stdin.buffer.readline().split()]
def I(): return int(sys.stdin.buffer.readline())
def LS():return [list(x) for x in sys.stdin.readline().split()]
def S():
res = list(sys.stdin.readline())
if res[-1] == "\n":
return res[:-1]
return res
def IR(n):
return [I() for i in range(n)]
def LIR(n):
return [LI() for i in range(n)]
def SR(n):
return [S() for i in range(n)]
def LSR(n):
return [LS() for i in range(n)]
sys.setrecursionlimit(1000000)
mod = 1000000007
def solve():
f = [1]
N = 1000000
for i in range(1,N+1):
f.append(f[-1]*i%mod)
inv = [None]*(N+1)
inv[N] = pow(f[N],mod-2,mod)
for i in range(N)[::-1]:
inv[i] = inv[i+1]*(i+1)%mod
def comb(a,b):
return f[a]*inv[b]*inv[a-b]%mod
h,w,a,b = LI()
ans = 0
y = h-a
x = b+1
while x <= w and y:
ans += comb(x+y-2,x-1)*comb(h-y+w-x,w-x)%mod
y -= 1
x += 1
print(ans%mod)
return
#Solve
if __name__ == "__main__":
solve()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s824602153 | p04046 | Accepted | memo=[0]*(10**6+1)
memo[0]=memo[1]=1
mod=10**9+7
for i in range(2,10**6+1):
memo[i]=(memo[i-1]*i)%mod
def comb(n,k,p):
return (memo[n]*pow(memo[k],p-2,p)*pow(memo[n-k],p-2,p))%mod
h,w,a,b=map(int,input().split())
ans=0
for i in range(h-a):
ans+=(comb(b+i-1,i,mod)*comb(h-i-1+w-b-1,w-b-1,mod))%mod
ans%=mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s941355053 | p04046 | Accepted | H, W, A, B = [int(_) for _ in input().split()]
mod = 10**9 + 7
X = [i for i in range(H + W + 1)]
X[0] = 1
for i in range(2, H + W + 1):
X[i] = X[i - 1] * i % mod
Y = X.copy()
Y[-1] = pow(Y[-1], mod - 2, mod)
for i in range(H + W, 1, -1):
Y[i - 1] = i * Y[i] % mod
def comb(x, y):
return X[x] * Y[y] * Y[x - y] % mod
ans = 0
for i in range(B, min(B + H - A, W)):
ans += comb(H - A + B - 1, i) * comb(W + A - B - 1, W - i - 1)
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s800338032 | p04046 | Accepted |
# Function to find modulo inverse of b. It returns
# -1 when inverse doesn't
# modInverse works for prime m
def gcd(b, m):
if b == 0:
return m
return gcd(m%b, b)
def modInverse(b,m):
g = gcd(b, m)
if (g != 1):
# print("Inverse doesn't exist")
return -1
else:
# If b and m are relatively prime,
# then modulo inverse is b^(m-2) mode m
return pow(b, m - 2, m)
# Function to compute a/b under modulo m
def modDivide(a,b,m):
a = a % m
inv = modInverse(b,m)
if(inv == -1):
print("Division not defined")
else:
return (inv*a) % m
MOD = (10 ** 9) + 7
H, W, A, B = list(map(int, input().split(' ')))
DP = []
j = 1
for i in range(1,200002):
j *= i
j %= MOD
DP.append(j)
# print(DP)
def factorial(i):
if (i == 0):
return 1
global DP
# print(i)
# print(i, DP[i-1])
# print(DP[i-1])
return DP[i-1]
def move2(H, W, A, B):
numPaths = 0
h = H-A
w = W-(W-B)+1
a = A+1
pttp = 0
for b in range(w, W+1):
# print(h, b, a, W-b+1)
ttp = (factorial(h+b-2)*modInverse((factorial(h-1)*factorial(b-1))% MOD, MOD)) % MOD
tpttp = ttp
ttp -= pttp
pttp = tpttp
btp = (factorial(a+(W-b+1)-2)*modInverse((factorial(a-1)*factorial(W-b))% MOD, MOD)) % MOD
# btp = factorial(a+(W-b+1)-2)//(factorial(a-1)*factorial(W-b))
numPaths += ttp*btp
return numPaths
ways = move2(H, W, A, B)
print(ways % (10**9 + 7)) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s902230742 | p04046 | Accepted | MOD = 10**9+7
def modpow(base, pow, mod):
res = 1
while pow > 0:
if pow & 1:
res = res * base % mod
base = base**2 % mod
pow >>= 1
return res
def modmul(a, b, mod):
return a*b % mod
def solve(h,w,a,b):
fact = [0]*(h+w+1)
fact[0] = 1
fact_inv = [0]*(h+w+1)
fact_inv[0] = 1
for i in range(1, h+w):
fact[i] = fact[i-1]*i % MOD
fact_inv[i] = modpow(fact[i], MOD-2, MOD)
ans = 0
for col_idx in range(b, w):
before_checkpoint = modmul(modmul(fact[h-a-1+col_idx], fact_inv[h-a-1], MOD), fact_inv[col_idx], MOD)
from_checkpoint = modmul(modmul(fact[(a-1) + (w-col_idx-1)], fact_inv[w-col_idx-1], MOD), fact_inv[a-1], MOD)
ans = (ans + modmul(before_checkpoint, from_checkpoint, MOD)) % MOD
return ans
if __name__ == "__main__":
h,w,a,b = map(int, input().split())
print(solve(h,w,a,b))
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s718583588 | p04046 | Accepted | h, w, a, b = [int(i) for i in input().split()]
mod = 10 ** 9 + 7
kkai = [1]
for i in range(1, 210000):
kkai.append(kkai[-1] * i % mod)
def kai(x, p=mod):
return kkai[x]
def comb(a, b, p=mod):
if a < 0 or b < 0:
return 0
elif a < b:
return 0
c = 1
c *= kai(a, p)
c *= pow(kai(b, p), p - 2, p)
c *= pow(kai(a - b, p), p - 2, p)
return c % p
ans = 0
for i in range(b, w):
ans += comb(i+(h-a)-1, i)*comb((w-i)+a-2, a-1)
ans %= mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s952392467 | p04046 | Accepted | H,W,A,B = map(int,input().split())
class Combination:
"""
O(n)の前計算を1回行うことで，O(1)でnCr mod mを求められる
n_max = 10**6のとき前処理は約950ms (PyPyなら約340ms, 10**7で約1800ms)
使用例：
comb = Combination(1000000)
print(comb(5, 3)) # 10
"""
def __init__(self, n_max, mod=10 ** 9 + 7):
self.mod = mod
self.modinv = self.make_modinv_list(n_max)
self.fac, self.facinv = self.make_factorial_list(n_max)
def __call__(self, n, r):
return self.fac[n] * self.facinv[r] % self.mod * self.facinv[n - r] % self.mod
def make_factorial_list(self, n):
# 階乗のリストと階乗のmod逆元のリストを返す O(n)
# self.make_modinv_list()が先に実行されている必要がある
fac = [1]
facinv = [1]
for i in range(1, n + 1):
fac.append(fac[i - 1] * i % self.mod)
facinv.append(facinv[i - 1] * self.modinv[i] % self.mod)
return fac, facinv
def make_modinv_list(self, n):
# 0からnまでのmod逆元のリストを返す O(n)
modinv = [0] * (n + 1)
modinv[1] = 1
for i in range(2, n + 1):
modinv[i] = self.mod - self.mod // i * modinv[self.mod % i] % self.mod
return modinv
comb = Combination(1000000)
MOD = 10**9+7
ans = 0
for i in range(B,W):
ans += comb(H-A-1+i,i)*comb(A-1+W-1-i,A-1)
ans %= MOD
#print(comb(H-A-1+i,i)*comb(A-1+W-1-i,A-1))
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s711753237 | p04046 | Accepted | #!/usr/bin/env python3
import sys
sys.setrecursionlimit(10**8)
INF = float("inf")
MOD = 1000000007 # type: int
class Combination(object):
def __init__(self, N, mod=MOD):
fac, finv, inv = [0]*(N+1), [0]*(N+1), [0]*(N+1)
fac[:2] = 1, 1
finv[:2] = 1, 1
inv[1] = 1
for i in range(2, N+1):
fac[i] = fac[i-1]*i % mod
inv[i] = -inv[mod % i]*(mod//i) % mod
finv[i] = finv[i-1]*inv[i] % mod
self.N = N
self.MOD = mod
self.fac = fac
self.finv = finv
self.inv = inv
def __call__(self, n, k):
if n < k:
return 0
if n < 0 or k < 0:
return 0
fac = self.fac
finv = self.finv
mod = self.MOD
return fac[n] * (finv[k]*finv[n-k] % mod) % mod
def solve(H: int, W: int, A: int, B: int):
cmb = Combination(H+W+1, MOD)
ans = 0
for i in range(B, W):
buf = cmb(H-A-1+i, i)
buf *= cmb(A+W-i-2, W-i-1)
buf %= MOD
ans += buf
ans %= MOD
print(ans)
return
def main():
def iterate_tokens():
for line in sys.stdin:
for word in line.split():
yield word
tokens = iterate_tokens()
H = int(next(tokens)) # type: int
W = int(next(tokens)) # type: int
A = int(next(tokens)) # type: int
B = int(next(tokens)) # type: int
solve(H, W, A, B)
if __name__ == '__main__':
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s937115372 | p04046 | Accepted | H, W, A, B = map(int, input().split())
MOD = 1000000007
fac = [1, 1]
inverse = [0, 1]
ifac = [1, 1]
for i in range(2, H+W):
fac.append((fac[-1] * i) % MOD)
inverse.append((-inverse[MOD % i] * (MOD // i)) % MOD)
ifac.append((ifac[-1] * inverse[i]) % MOD)
def f(n):
return fac[B+n+H-A-1] * fac[W-B-1-n+A-1] * ifac[B+n] * ifac[H-A-1] * ifac[W-B-1-n] * ifac[A-1]
def sigma(func, frm, to):
result = 0
for i in range(frm, to+1):
result += func(i)
return result
print(sigma(f, 0, W-B-1)%MOD)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s669159115 | p04046 | Accepted | H,W,A,B=map(int,input().split())
MAX_NUM = 2*10**5 + 1
pr = 10**9+7
fac = [0 for _ in range(MAX_NUM)]
finv = [0 for _ in range(MAX_NUM)]
inv = [0 for _ in range(MAX_NUM)]
fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2,MAX_NUM):
fac[i] = fac[i-1] * i % pr
inv[i] = pr - inv[pr%i] * (pr // i) % pr
finv[i] = finv[i-1] * inv[i] % pr
def c(n,k):
if n < k:
return 0
if n < 0 or k < 0:
return 0
return fac[n] * (finv[k] * finv[n-k] % pr) % pr
a=0
while 1:
a=(a+c(H-A-1+B,B)*c(A+W-B-1,A))%pr
A+=1
B+=1
if A==H or B==W:
break
print(a) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s380631765 | p04046 | Accepted | from operator import mul
from functools import reduce
def cmb(n, r, p):
if (r < 0) or (n < r):
return 0
r = min(r, n - r)
return fact[n] * factinv[r] * factinv[n-r] % p
p = 10 ** 9 + 7
N = 10 ** 6
fact = [1, 1] # fact[n] = (n! mod p)
factinv = [1, 1] # factinv[n] = ((n!)^(-1) mod p)
inv = [0, 1]
for i in range(2, N + 1):
fact.append((fact[-1] * i) % p)
inv.append((-inv[p % i] * (p // i)) % p)
factinv.append((factinv[-1] * inv[-1]) % p)
#kari1 = '2 3 1 1' #2
#kari1 = '10 7 3 4' #3570
#kari1 = '100000 100000 99999 99999' #1
#kari1 = '100000 100000 44444 55555' #738162020
"""
in1 = kari1.split()
"""
in1 = input().split()
H = int(in1[0])
W = int(in1[1])
A = int(in1[2])
B = int(in1[3])
allCNT = 0
for idx1 in range(W - B):
beforeCNT = cmb(H - A + B - 1 + idx1, H - A - 1, p)
afterCNT = cmb(W + A - B - 2 - idx1, A - 1, p)
allCNT = (allCNT + (beforeCNT * afterCNT) % p) % p
print(allCNT)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s651322526 | p04046 | Accepted | mod = 10 ** 9 + 7
def extGCD(a, b):
if b == 0:
return a, 1, 0
g, y, x = extGCD(b, a%b)
y -= a//b * x
return g, x, y
def moddiv(a, b):
_, inv, _ = extGCD(b, mod)
return (a * inv) % mod
N = 2 * 10 ** 5 + 10
fact = [0] * (N)
fact[0] = 1
for i in range(1, N):
fact[i] = (fact[i-1] * i) % mod
def comb(a, b):
return moddiv(moddiv(fact[a], fact[a-b]), fact[b])
h, w, a, b = map(int, input().split())
ans = 0
for i in range(min(h-a, w-b)):
x = h - 1 - a - i
y = b + i
plus = comb(x + y, x) * comb((h-1 - x) + (w-1 - y), (h-1 - x))
ans += plus
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s866868141 | p04046 | Accepted | h, w, a, b = map(int, input().split())
MOD = 1000000007
def modPow(a, x, p):
res = 1
while (x > 0):
if (x % 2 != 0):
res = (res * a) % p
a = (a * a) % p
x /= 2
return res
fact = [None] * 220000
for i in range(1, 220000):
fact[0] = 1
fact[i] = i * fact[i - 1] % MOD
# inv[i] = modPow(fact[i], MOD-2, MOD)
def ncr(n, r):
den = fact[n - r] * fact[r] % MOD
return fact[n] * pow(den, MOD - 2, MOD) % MOD
def number_of_paths(h, w):
n = h + w - 2
r = h - 1
return ncr(n, r)
ans = 0
for i in range(b + 1, w + 1):
# print('first', h-a, i)
ans += number_of_paths(h - a, i) * number_of_paths(a, w - i + 1)
print(int(ans % MOD))
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s075777515 | p04046 | Accepted | h,w,a,b = map(int, input().split())
def find_power(n,mod=10**9+7):
powlist=[0]*(n+1)
powlist[0]=1
powlist[1]=1
for i in range(2,n+1):
powlist[i]=powlist[i-1]*i%(mod)
return powlist
def find_inv_power(n):
powlist=find_power(n)
check=powlist[-1]
first=1
uselist=[0]*(n+1)
secondlist=[0]*30
secondlist[0]=check
secondlist[1]=check**2
for i in range(28):
secondlist[i+2]=(secondlist[i+1]**2)%(10**9+7)
a=format(10**9+5,"b")
for j in range(30):
if a[29-j]=="1":
first=(first*secondlist[j])%(10**9+7)
uselist[n]=first
for i in range(n,0,-1):
uselist[i-1]=(uselist[i]*i)%(10**9+7)
return uselist
mod = 10**9+7
p_lis=find_power(4*10**5+100,mod)
ip_lis=find_inv_power(4*10**5+100)
def comb(n,r,mod=10**9+7):
if n<r:
return 0
elif n>=r:
return (p_lis[n]*ip_lis[r]*ip_lis[n-r])%(mod)
ans=0
for i in range(h-a):
pre=comb(i+b-1,i)
post=comb(h+w-b-2-i,h-i-1)
ans+=pre*post
ans%=10**9+7
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s907387093 | p04046 | Accepted | import sys
input = sys.stdin.readline
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))
def main():
mod=10**9+7
H,W,A,B=MI()
N=H+W
def cmb(n, r, mod):
if (r < 0) or (n < r):
return 0
r = min(r, n - r)
return (fact[n] * factinv[r] * factinv[n-r])%mod
fact=[1,1]
factinv=[1,1]
inv=[0,1]
for i in range(2, N + 1):
fact.append((fact[-1] * i) % mod)
inv.append((-inv[mod % i] * (mod // i)) % mod)
factinv.append((factinv[-1] * inv[-1]) % mod)
ans=cmb(N-2,H-1,mod)
for i in range(min(A,B)):
h=H-A+i+1
w=B-i
#print(h,w,cmb(h+w-2,h-1,mod),cmb(H+W-(h+w),H-h,mod))
ans-=cmb(h+w-2,h-1,mod)*cmb(H+W-(h+w),H-h,mod)
ans%=mod
print(ans%mod)
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s337405092 | p04046 | Accepted | N=2*10**5+3
mod=10**9+7
fac=[1]*(N+1)
for i in range(1,N+1):
fac[i]=fac[i-1]*i%mod
inv_fac=[1]*(N+1)
inv_fac[N]=pow(fac[N],mod-2,mod)
for i in range(N-1,0,-1):
inv_fac[i]=inv_fac[i+1]*(i+1)%mod
def nCr(n,r):
if n<0 or r<0 or r>n:
return 0
return fac[n]*inv_fac[r]%mod*inv_fac[n-r]%mod
h,w,a,b=map(int,input().split())
ans=nCr(h+w-2,h-1)
for i in range(b):
ans=(ans-nCr(h-a+i-1,i)*nCr(a+w-i-2,a-1))%mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s715567132 | p04046 | Accepted |
class Cmber:
def __init__(self,gensize,mod=10**9+7):
self.mod = mod
self.g1=[1,1]
self.g2 = [1, 1] #逆元テーブル
self.inverse = [0, 1] #逆元テーブル計算用テーブル
self.getgen(gensize)
def getgen(self,N):
for i in range( 2, N + 1 ):
self.g1.append( ( self.g1[-1] * i ) % self.mod )
self.inverse.append( ( -self.inverse[self.mod % i] * (self.mod//i) ) % self.mod )
self.g2.append( (self.g2[-1] * self.inverse[-1]) % self.mod )
def cmb(self,n, r):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return self.g1[n] * self.g2[r] * self.g2[n-r] % self.mod
def cmb_very_high_n(self,n, r):
if ( r<0 or r>n ):
return 0
g1=1
r = min(r, n-r)
for i in range(n-r+1,n+1):
g1*=i
g1%=self.mod
return g1 * self.g2[r] % self.mod
def resolve():
H,W,A,B= map(int,input().split())
cmb= Cmber(H+W+1)
sm =0
for i in range(H-A):
bef = cmb.cmb(B+i-1,i)
r=W-B-1
u=H-i-1
aft = cmb.cmb(r+u,u)
sm += (aft*bef) % 1000000007
sm %= 1000000007
# print(i,r,u,bef,aft)
print(sm)
if __name__ == "__main__":
resolve() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s989067102 | p04046 | Accepted | h,w,a,b=map(int,input().split())
N=h+w
mod=10**9+7
fac=[1]*(N+2)
inv=[1]*(N+2)
t=1
for i in range(1,N+2):
t*=i
t%=mod
fac[i]=t
t=pow(fac[N+1],mod-2,mod)
for i in range(N+1,0,-1):
inv[i]=t
t*=i
t%=mod
def comb(n,r):
return fac[n]*inv[n-r]*inv[r]%mod
c=[0]
for i in range(h-a):
c.append(comb(b+i,i))
ans=0
for i in range(h-a):
ans+=(c[i+1]-c[i])*comb(w-b+h-i-2,w-b-1)%mod
ans%=mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s985696220 | p04046 | Accepted | h,w,a,b=map(int,input().split())
mod=10**9+7
ans=0
def cmb(n, r, mod):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
mod = 10**9+7 #出力の制限
N = h+w+1
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
for i in range( 2, N + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
#a = cmb(n,r,mod)
for i in range(h-a):
p=(i)+(b-1)
q=(h-i-1)+((w-b)-1)
ans+=cmb(p,i,mod)*cmb(q,h-i-1,mod)
ans%=mod
#print(p,q)
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s435632479 | p04046 | Accepted | import math
h, w, a, b = map(int, input().split())
#divmod
mod = pow(10,9)+7
def divmod(num, mod=10**9+7):
return pow(num, mod-2, mod)
#combination
def comb(a,b):
p=fact[a-b]*fact[b]%mod
return fact[a]*divmod(p)%mod
fact = [1]
for i in range(1,h+w):
fact.append(i*fact[i-1]%mod)
#print(fact)
ans = 0
for j in range(h-a):
tmp = comb(b-1+j,j)*comb(w+h-b-2-j,w-b-1)%mod
ans += tmp
ans = ans%mod
# ans = ans + fact[b-1+j]*fact[w+h-b-2-j]/fact[b-1]/fact[j]/fact[w-b-1]/fact[h-1-j]
print(int(ans))
'''
単純なh*wのマス目だった場合
#h-row / w-col
con = [[0]*w]*h
for i in range(h):
con[i][0] = 1
for j in range(w):
con[0][j] = 1
for k in range(1,h):
for l in range(1,w):
con[k][l] = con[k-1][l] + con[k][l-1]
print(con[h-1][w-1])
'''
'''
全量を計算するやり方
H*Wがデカすぎると時間というよりもメモリエラー
print('initialize')
con = [[0 for i in range(w)] for j in range(h)]
#リスト内包表記で作らないとバグる
#ダメな例 -> con = [[0]*w]*h
#https://qiita.com/utgwkk/items/5ad2527f19150ae33322
print('initialize finished')
for i in range(h-a):
con[i][0] = 1
#print(con[0])
for j in range(w):
#wは先に初期化やっちゃう
con[0][j] = 1
#print(con)
for k in range(1,h-a):
# print(k)
for l in range(1,b+1):
con[k][l] = con[k-1][l] + con[k][l-1]
#print(con[h-a-1][b-1])
#print(con[h-a][b-1])
#print(con[h-a-1][b])
for m in range(1,h):
# print('---{} row---'.format(m))
# print(con[m])
for n in range(b,w):
# print('m,n:('+str(m)+','+str(n)+')')
con[m][n] = con[m-1][n] + con[m][n-1]
# print(con[m])
print(con[h-1][w-1])
'''
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s530108711 | p04046 | Accepted | class ModInt:
def __init__(self, num, mod):
self.num = num
self.mod = mod
def __str__(self):
return str(self.num)
def __repr__(self):
return "ModInt(num: {}, mod: {}".format(self.num, self.mod)
def __add__(self, other):
ret = self.num + other.num
ret %= self.mod
return ModInt(ret, self.mod)
def __sub__(self, other):
ret = self.num - other.num
ret %= self.mod
return ModInt(ret, self.mod)
def __mul__(self, other):
ret = self.num * other.num
ret %= self.mod
return ModInt(ret, self.mod)
def pow(self, times):
pw = pow(self.num, times, self.mod)
return ModInt(pw, self.mod)
def inverse(self):
return self.pow(self.mod - 2)
def __truediv__(self, other):
num = self * other.inverse()
return ModInt(num, self.mod)
h, w, a, b = map(int, input().split())
mod = 10 ** 9 + 7
fact = [ModInt(1, mod)]
inv = [ModInt(1, mod).inverse()] * (h + w - 1)
def comb(n, r):
return fact[n] * inv[r] * inv[n-r]
for i in range(1, h + w - 1):
fact.append(fact[-1] * ModInt(i, mod))
inv[h+w-2] = fact[-1].inverse()
for i in range(h + w - 2, 0, -1):
inv[i-1] = inv[i] * ModInt(i, mod)
ans = ModInt(0, mod)
for hi in range(h - a):
ans += comb(hi + b - 1, hi) * comb(h - hi - 1 + w - b - 1, w - b - 1)
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s500868525 | p04046 | Accepted | mod=10**9+7
h,w,a,b=map(int,input().split())
def comb(a,b):
p=fac[a-b]*fac[b]%mod
return fac[a]*pow(p,mod-2,mod)%mod
fac=[1]
for i in range(h+w):
fac.append(fac[-1]*(i+1)%mod)
ans=0
for i in range(w-b):
p=comb(h-a-1+b+i,b+i)*comb(w-b-i-2+a,a-1)
ans+=p%mod
ans%=mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s091927857 | p04046 | Accepted | import math
from functools import reduce
from collections import deque
import sys
sys.setrecursionlimit(10**7)
# スペース区切りの入力を読み込んで数値リストにして返します。
def get_nums_l():
return [ int(s) for s in input().split(" ")]
# 改行区切りの入力をn行読み込んで数値リストにして返します。
def get_nums_n(n):
return [ int(input()) for _ in range(n)]
# 改行またはスペース区切りの入力をすべて読み込んでイテレータを返します。
def get_all_int():
return map(int, open(0).read().split())
def log(*args):
print("DEBUG:", *args, file=sys.stderr)
def init_kaijo(MAX, MOD):
kaijo = [0] * MAX
kaijo[0] = 1
for i in range(1, len(kaijo)):
kaijo[i] = kaijo[i-1] * i % MOD
return kaijo
MOD = 10**9+7
kaijo = init_kaijo(500000, MOD)
def inv(x, MOD):
return pow(x, MOD-2, MOD)
def nPk(n, k, MOD):
return kaijo[n] * inv(kaijo[n-k], MOD) % MOD
def nCk(n, k, MOD):
# log("{}C{} = {}".format(n,k,nPk(n,k, MOD) * inv(kaijo[k], MOD)))
return nPk(n,k, MOD) * inv(kaijo[k], MOD)
h, w, a, b = get_nums_l()
ans = 0
for i in range(h-a):
# (0,0)から(b-1, i)に到着するパターン数 * (b,i)から(W-1, H-1)に到着するパターン数
# log(nCk(b+i-1, i, MOD), nCk(w-b+h-i-2, h-i-1, MOD))
ans += nCk(b+i-1, i, MOD) * nCk(w-b+h-i-2, h-i-1, MOD) % MOD
print(ans % MOD)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s743875436 | p04046 | Accepted | # D - いろはちゃんとマス目
def cmb1(n,r,mod):
if (r<0 or r>n):
return 0
r = min(r,n-r)
return g1[n]*g2[r]*g2[n-r]%mod
h,w,a,b=map(int,input().split())
# 前処理
mod=10**9+7 #出力の制限
n=10**6
g1=[1,1] # 元テーブル
g2=[1,1] # 逆元テーブル
inverse=[0,1] #逆元テーブル計算用テーブル
for i in range(2,n+1):
g1.append((g1[-1]*i)%mod)
inverse.append((-inverse[mod%i]*(mod//i))%mod)
g2.append((g2[-1]*inverse[-1])%mod)
ans = 0
for i in range(b, w):
ans+=cmb1(i+h-1-a,i,mod)*cmb1(w-1-i+a-1,a-1,mod)
ans%=mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s038983669 | p04046 | Accepted | h, w, a, b = map(int, input().split())
def cmb1(n, r, mod):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
mod = 10**9+7 #出力の制限
N = 10**6
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
for i in range( 2, N + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
ans = 0
for i in range(b, w):
ans += cmb1(i+h-1-a, i, mod)*cmb1(w-1-i+a-1, a-1, mod)
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s816650220 | p04046 | Accepted | def main():
H, W, A, B = (int(i) for i in input().split())
m = H + W + 3
MOD = 10**9 + 7
fac = [0] * m
finv = [0] * m
inv = [0] * m
def COMBinitialize(m):
fac[0] = 1
finv[0] = 1
if m > 1:
fac[1] = 1
finv[1] = 1
inv[1] = 1
for i in range(2, m):
fac[i] = fac[i-1] * i % MOD
inv[i] = MOD - inv[MOD % i] * (MOD // i) % MOD
finv[i] = finv[i - 1] * inv[i] % MOD
def COMB(n, k):
if n < k:
return 0
if n < 0 or k < 0:
return 0
return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD
COMBinitialize(m)
ans = 0
for x in range(W-B):
if x == 0:
p = COMB(H-A-1 + B+x, B+x)
else:
p = COMB(H-A-1 + B+x, B+x) - COMB(H-A-1 + B+x-1, B+x-1)
q = COMB(A+W-1-B-x, A)
ans += p*q
ans %= MOD
print(ans % MOD)
if __name__ == '__main__':
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s313640545 | p04046 | Accepted | MOD = 10**9+7
fac = [1 for k in range(200010)]
inv = [1 for k in range(200010)]
finv = [1 for k in range(200010)]
for k in range(2,200010):
fac[k] = (fac[k-1]*k)%MOD
inv[k] = (MOD - inv[MOD%k] * (MOD // k))%MOD
finv[k] = (finv[k - 1] * inv[k]) % MOD;
def nCr(n,r):
return (fac[n]*finv[r]*finv[n-r])%MOD
H, W, A, B = map(int,input().split())
ans = 0
for k in range(W-B):
ans += nCr(A+W-B-k-2,A-1)*nCr(B+k+1+H-A-2,H-A-1)
ans %= MOD
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s348368747 | p04046 | Accepted | class Combination():
# コンストラクタ
def __init__(self, N:int, P:int):
self.N = N
self.P = P
# fact[i] = (i! mod P)
self.fact = [1, 1]
# factinv[i] = ((i!)^(-1) mod P)
self.factinv = [1, 1]
# factinv 計算用
self.inv = [0, 1]
for i in range(2, N+1):
self.fact.append((self.fact[-1] * i) % P)
self.inv.append((-self.inv[P % i] * (P // i)) % P)
self.factinv.append((self.factinv[-1] * self.inv[-1]) % P)
# nCk (mod P) (ただし、n<=N)
def getComb(self, n:int, k:int):
if (k < 0) or (n < k):
return 0
k = min(k, n - k)
return self.fact[n] * self.factinv[k] * self.factinv[n-k] % self.P
def main():
H,W,A,B = map(int,input().split())
MOD = 10**9 + 7
COMB = Combination(H+W, MOD)
# (1,1) -> (i,B-1) -> (i,B+1) -> (H,W)
ans = 0
for i in range(1,H-A+1):
tmp = COMB.getComb((i-1)+(B-1), i-1)
tmp *= COMB.getComb((H-i)+(W-B-1), H-i)
ans = (ans + tmp) % MOD
print(ans)
if __name__ == "__main__":
main() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s669878261 | p04046 | Accepted | H,W,A,B = map(int, input().split())
def cmb(n, r, mod):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
mod = 10**9+7 #出力の制限
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
for i in range( 2, H+W + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
ans = 0
for h in range(1, H-A+1):
ans += cmb(h-1+B-1, h-1, mod)*cmb(H-h+W-B-1, H-h, mod)
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s077226498 | p04046 | Accepted | import sys
def comb(n, r, fact, revfact, mod):
return (fact[n] * revfact[n-r] * revfact[r]) % mod
def solve():
H, W, A, B = map(int, input().split())
mod = 7 + 10 ** 9
fact = [1] * (H + W + 4)
revfact = [1] * (H + W + 4)
for i in range(1, H + W + 4): fact[i] = (i * fact[i-1]) % mod
revfact[H + W + 3] = pow(fact[H + W + 3], mod - 2, mod)
for i in reversed(range(1, H + W + 3)): revfact[i] = ((i + 1) * revfact[i + 1]) % mod
ans = 0
for j in range(B + 1, W + 1):
up = comb(H - A + j - 2, j - 1, fact, revfact, mod)
down = comb(A + W - j - 1, A - 1, fact, revfact, mod)
ans += (up * down) % mod
ans %= mod
print(ans)
return 0
if __name__ == "__main__":
solve() | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s161678019 | p04046 | Accepted | import sys
mod = pow(10, 9) + 7
sys.setrecursionlimit(pow(10, 8))
def power(x, y):
if y == 0: return 1
elif y == 1 : return x % mod
elif y % 2 == 0 : return power(x, y//2)**2 % mod
else: return power(x, (y-1)//2)**2 * x % mod
def mul(a, b):
return ((a % mod) * (b % mod)) % mod
def div(a, b):
return mul(a, power(b, mod-2))
def div2(a, b):
return mul(a, modinv(b))
def modinv(a):
b, u, v = mod, 1, 0
while b:
t = a//b
a, u = a-t*b, u-t*v
a, b, u, v = b, a, v, u
u %= mod
return u
def cmb(n, r):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
NNN = (10**6)
g1 = [1, 1]
g2 = [1, 1]
inverse = [0, 1]
for i in range( 2, NNN + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
H, W, A, B = map(int, input().split())
r = 0
for i in range(H-A):
# (0, 0) -> (i, B-1)
# (i, B) -> (H-1, W-1)
r = (r + mul(cmb(i+B-1, i), cmb(H-1-i+W-1-B, H-1-i)))%mod
print(r)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s058736282 | p04046 | Accepted | class Combination:
"""
SIZEが10^6程度以下の二項係数を何回も呼び出したいときに使う
使い方:
comb = Combination(SIZE, MOD)
comb(10, 3) => 120
"""
def __init__(self, N, MOD=10 ** 9 + 7):
self.MOD = MOD
self.fact, self.inv = self._make_factorial_list(N)
def __call__(self, n, k):
if k < 0 or k > n:
return 0
res = self.fact[n] * self.inv[k] % self.MOD
res = res * self.inv[n - k] % self.MOD
return res
def _make_factorial_list(self, N):
fact = [1] * (N + 1)
inv = [1] * (N + 1)
MOD = self.MOD
for i in range(1, N + 1):
fact[i] = (fact[i - 1] * i) % MOD
inv[N] = pow(fact[N], MOD - 2, MOD)
for i in range(N, 0, -1):
inv[i - 1] = (inv[i] * i) % MOD
return fact, inv
if __name__ == "__main__":
H, W, A, B = map(int, input().split())
mod = 10 ** 9 + 7
comb = Combination(2 * 10 ** 5 + 10, mod)
ans = 0
x = H - A
y = B + 1
while x > 0 and y <= W:
path1 = comb(x + y - 2, x - 1)
path2 = comb(H - x + W - y, H - x)
ans = (ans + path1*path2) % mod
x -= 1
y += 1
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s638339919 | p04046 | Accepted | MAX = 2*10**5+100
fact = [0]*MAX
inv = [0]*MAX
finv = [0]*MAX
def C_init():
fact[0] = 1
fact[1] = 1
finv[0] = 1
finv[1] = 1
inv[1] = 1
for i in range(2, MAX):
fact[i] = fact[i-1]*i%MOD
inv[i] = MOD-inv[MOD%i]*(MOD//i)%MOD
finv[i] = finv[i-1]*inv[i]%MOD
def C(n, r):
if n<r:
return 0
if n<0 or r<0:
return 0
return fact[n]*(finv[r]*finv[n-r]%MOD)%MOD
H, W, A, B = map(int, input().split())
MOD = 10**9+7
C_init()
ans = 0
for i in range(H-A):
ans += C(i+B-1, i)*C(H-1-i+W-B-1, W-B-1)
ans %= MOD
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s740150393 | p04046 | Accepted | h, w, a, b = map(int, input().split())
mod = 10**9 + 7
fac = [1, 1]
inv = [1, 1]
finv = [1, 1]
for i in range(2, h+w+5):
fac.append(fac[i-1] * i % mod)
inv.append(mod - inv[mod%i] * (mod//i) % mod)
finv.append(finv[i-1] * inv[i] % mod)
def nck(n, k):
if n < k:
return 0
if n < 0 or k < 0:
return 0
return fac[n] * (finv[k] * finv[n-k] % mod) % mod
ans = 0
for i in range(h-a):
ans += nck(i+b-1, b-1) * nck(h-1-i + w-b-1, w-b-1) % mod
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s887423083 | p04046 | Accepted | class Combination:
"""
SIZEが10^6程度以下の二項係数を何回も呼び出したいときに使う
使い方:
comb = Combination(SIZE, MOD)
comb(10, 3) => 120
"""
def __init__(self, N, MOD=10 ** 9 + 7):
self.MOD = MOD
self.fact, self.inv = self._make_factorial_list(N)
def __call__(self, n, k):
if k < 0 or k > n:
return 0
res = self.fact[n] * self.inv[k] % self.MOD
res = res * self.inv[n - k] % self.MOD
return res
def _make_factorial_list(self, N):
fact = [1] * (N + 1)
inv = [1] * (N + 1)
MOD = self.MOD
for i in range(1, N + 1):
fact[i] = (fact[i - 1] * i) % MOD
inv[N] = pow(fact[N], MOD - 2, MOD)
for i in range(N, 0, -1):
inv[i - 1] = (inv[i] * i) % MOD
return fact, inv
if __name__ == "__main__":
H, W, A, B = map(int, input().split())
mod = 10**9+7
comb = Combination(2*10**5+10, mod)
ans = 0
h1 = H - A
w1 = B + 1
while True:
X = comb(h1 + w1 - 2, h1 - 1)
h2 = H - h1
w2 = W - w1
Y = comb(h2 + w2, h2)
ans += X * Y % mod
ans %= mod
h1 -= 1
w1 += 1
if h1 <= 0 or w1 > W:
break
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s778888518 | p04046 | Accepted | h,w,a,b = map(int, input().split())
mx = max(h,w)
mod = 10**9+7
fac = [1]*(h+w+1)
for i in range(1,h+w+1):
fac[i]=fac[i-1]*i%mod
rev = [1]*(mx+1)
rev[-1] = pow(fac[mx], mod-2, mod)
for i in range(mx-1, -1, -1):
rev[i] = rev[i+1]*(i+1)%mod
const = rev[h-a-1]*rev[a-1]%mod
ans = 0
for i in range(b,w):
ans += fac[h-a+i-1]*rev[i]*fac[a+w-2-i]*rev[w-i-1]%mod
print(ans*const%mod) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s479470866 | p04046 | Accepted | h, w, a, b = map(int, input().split())
m = 10**9 + 7
fac = [1, 1]
inv = [1, 1]
finv = [1, 1]
for i in range(2, w+h+5):
fac.append(fac[i-1] * i % m)
inv.append(m - inv[m%i] * (m//i) % m)
finv.append(finv[i-1] * inv[i] % m)
def nck(n, k):
if n < k:
return 0
if n < 0 or k < 0:
return 0
return fac[n] * (finv[k] * finv[n-k] % m) % m
row = []
for i in range(h-a):
row.append(nck(b+i, i))
ans = 0
for i in range(len(row)-1):
ans += row[i] * nck(w-b-2 + h-1-i, h-1-i)
ans %= m
ans += row[-1] * nck(w-b-1 + a, a)
ans %= m
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s147744319 | p04046 | Accepted | class Factorial:
def __init__(self, n, mod=10**9+7):
self.fac = [0] * (n+1)
self.ifac = [0] * (n+1)
self.fac[0] = 1
self.ifac[0] = 1
self.mod = mod
modmod = self.mod - 2
for i in range(n):
self.fac[i+1] = self.fac[i] * (i+1) % self.mod
self.ifac[i+1] = self.ifac[i] * pow(i+1, modmod, self.mod) % self.mod
def comb(self, n, r):
if n == 0 and r == 0:
return 1
if n < r or n < 0:
return 0
tmp = self.ifac[n-r] * self.ifac[r] % self.mod
return tmp * self.fac[n] % self.mod
def perm(self, n, r):
if n == 0 and r == 0:
return 1
if n < r or n < 0:
return 0
return (self.fac[n] * self.ifac[n-r]) % self.mod
h,w,a,b = map(int, input().split())
mod = 10**9+7
fact = Factorial(h+w+1)
ans = 0
c,d = h-a, w-b
for i in range(b+1, w+1):
d = w-i+1
# print(i,i+c-2, c-1, fact.comb(i+c-2, c-1), fact.comb(a+d-2, a-1))
ans = (ans + fact.comb(i+c-2, c-1) * fact.comb(a+d-2, a-1)) % mod
print(ans)
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s633470199 | p04046 | Accepted | H,W,A,B = map(int,input().split())
mod = 10**9+7
x1 = [1 for i in range(H+W)]
xi = [1 for i in range(H+W)]
num = 1
def power2(a,b,p):
if b == 0:
return 1
if b%2 == 0:
d = power2(a,b//2,p)
return (d*d)%p
return (a*power2(a,b-1,p))%p
for i in range(1,H+W):
num = (num*i)%mod
x1[i] = num
for i in range(1,H+W):
x2 = power2(x1[i],mod-2,mod)
xi[i] = x2
def comb(a,b,p):
return (x1[a]*xi[b]*xi[a-b])%p
ans = 0
for w in range(B,W):
ans = (ans+ (comb(H-A+w-1,w,mod)*comb(A+W-w-2,A-1,mod))%mod)%mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s585366330 | p04046 | Accepted | import sys
input = sys.stdin.buffer.readline
import copy
def main():
H,W,A,B = map(int,input().split())
MOD = 10**9+7
fac = [0 for _ in range(H+W+1)]
fac[0],fac[1] = 1,1
inv = copy.deepcopy(fac)
invfac = copy.deepcopy(fac)
for i in range(2,H+W+1):
fac[i] = (fac[i-1]*i)%MOD
inv[i] = MOD-(MOD//i)*inv[MOD%i]%MOD
invfac[i] = (invfac[i-1]*inv[i])%MOD
def coef(x,y):
num = (((fac[x+y]*invfac[x])%MOD)*invfac[y]%MOD)
return num
ans = 0
for i in range(H-A):
able = coef(i,B-1)*coef(H-i-1,W-B-1)
ans += able
ans %= MOD
print(ans)
if __name__ == "__main__":
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s431447671 | p04046 | Accepted | H, W, A, B = map(int, input().split())
mod = 10**9+7
F = [1]*200010
p = 1
for i in range(1, len(F)):
F[i] = p = p*i%mod
def comb(n, k):
return F[n]*pow(F[n-k], mod-2, mod)*pow(F[k], mod-2, mod)%mod
ans = 0
for h in range(H-A):
x = comb(B-1+h, h) # 右にB-1回、下にh回移動する方法の数
y = comb(W+H-B-h-2, H-h-1) # 右にW-B-1回、下にH-h-1回移動する方法の数
ans += x*y
ans %= mod
print(ans) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s531459836 | p04046 | Accepted | mod = 10**9 + 7
h, w, a, b = map(int, input().split())
fact = [1] * (h + w + 1)
invf = [1] * (h + w + 1)
invn = [1] * (h + w + 1)
for i in range(2, h + w + 1):
fact[i] = fact[i-1] * i % mod
invn[i] = (-invn[mod % i]) * (mod // i) % mod
invf[i] = invf[i-1] * invn[i] % mod
count = 0
for i in range(min(h-a, w-b)):
count += fact[h+b-a-1] * invf[h-a-i-1] * invf[b+i] * fact[w+a-b-1] * invf[a+i] * invf[w-b-i-1]
count %= mod
print(count) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s697581947 | p04046 | Accepted | H,W,A,B = map(int,input().split())
def cmb(n, r, mod):
if ( r<0 or r>n ):
return 0
r = min(r, n-r)
return g1[n] * g2[r] * g2[n-r] % mod
N = 10**6 #出力の制限
mod = 10**9+7
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
for i in range( 2, N + 1 ):
g1.append( ( g1[-1] * i ) % mod )
inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
g2.append( (g2[-1] * inverse[-1]) % mod )
def path(a,b):
h=b[0]-a[0]
w=b[1]-a[1]
return cmb(h+w,h,mod)
st,gl = [0,0],[H-1,W-1]
ans = path(st,gl)
for i in range(A):
ans-=(path(st,[H-i-1,B-1])*path([H-i-1,B],gl))%mod
print(ans%mod) | 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
s849254979 | p04046 | Accepted | import sys
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
MOD = 10**9+7
fac = [1, 1]
f_inv = [1, 1]
inv = [0, 1]
def modcmb(n, r, mod):
if n < 0 or r < 0 or r > n:
return 0
return fac[n] * f_inv[r] * f_inv[n-r] % mod
def main():
H,W,A,B = map(int, readline().split())
n = H+W+1
for i in range(2,n):
fac.append((fac[-1] * i) % MOD)
inv.append((-inv[MOD % i] * (MOD//i)) % MOD)
f_inv.append((f_inv[-1] * inv[-1]) % MOD)
ans = 0
for i in range(H-A):
ans += modcmb(B-1+i, B-1, MOD) * modcmb(H+W-B-2-i, W-1-B, MOD) % MOD
ans %= MOD
print(ans)
if __name__ == "__main__":
main()
| 2 3 1 1
| 2
| <span class="lang-en">
<p>Score : <var>400</var> points</p>
<div class="part">
<section>
<h3>Problem Statement</h3><p>We have a large square grid with <var>H</var> rows and <var>W</var> columns.
Iroha is now standing in the top-left cell.
She will repeat going right or down to the adjacent cell, until she reaches the bottom-right cell.</p>
<p>However, she cannot enter the cells in the intersection of the bottom <var>A</var> rows and the leftmost <var>B</var> columns. (That is, there are <var>A×B</var> forbidden cells.) There is no restriction on entering the other cells.</p>
<p>Find the number of ways she can travel to the bottom-right cell.</p>
<p>Since this number can be extremely large, print the number modulo <var>10^9+7</var>.</p>
</section>
</div>
<div class="part">
<section>
<h3>Constraints</h3><ul>
<li><var> 1 ≦ H, W ≦ 100,000</var></li>
<li><var> 1 ≦ A < H</var></li>
<li><var> 1 ≦ B < W</var></li>
</ul>
</section>
</div>
<hr/>
<div class="io-style">
<div class="part">
<section>
<h3>Input</h3><p>The input is given from Standard Input in the following format:</p>
<pre><var>H</var> <var>W</var> <var>A</var> <var>B</var>
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Output</h3><p>Print the number of ways she can travel to the bottom-right cell, modulo <var>10^9+7</var>.</p>
</section>
</div>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 1</h3><pre>2 3 1 1
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 1</h3><pre>2
</pre>
<p>We have a <var>2×3</var> grid, but entering the bottom-left cell is forbidden. The number of ways to travel is two: "Right, Right, Down" and "Right, Down, Right".</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 2</h3><pre>10 7 3 4
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 2</h3><pre>3570
</pre>
<p>There are <var>12</var> forbidden cells.</p>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 3</h3><pre>100000 100000 99999 99999
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 3</h3><pre>1
</pre>
</section>
</div>
<hr/>
<div class="part">
<section>
<h3>Sample Input 4</h3><pre>100000 100000 44444 55555
</pre>
</section>
</div>
<div class="part">
<section>
<h3>Sample Output 4</h3><pre>738162020
</pre></section>
</div>
</span> |
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