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Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Two players play a game. The game is played on a rectangular board with n × m squares. At the beginning of the game two different squares of the board have two chips. The first player's goal is to shift the chips to the same square. The second player aims to stop the first one with a tube of superglue.
We'll describe the rules of the game in more detail.
The players move in turns. The first player begins.
With every move the first player chooses one of his unglued chips, and shifts it one square to the left, to the right, up or down. It is not allowed to move a chip beyond the board edge. At the beginning of a turn some squares of the board may be covered with a glue. The first player can move the chip to such square, in this case the chip gets tightly glued and cannot move any longer.
At each move the second player selects one of the free squares (which do not contain a chip or a glue) and covers it with superglue. The glue dries long and squares covered with it remain sticky up to the end of the game.
If, after some move of the first player both chips are in the same square, then the first player wins. If the first player cannot make a move (both of his chips are glued), then the second player wins. Note that the situation where the second player cannot make a move is impossible — he can always spread the glue on the square from which the first player has just moved the chip.
We will further clarify the case where both chips are glued and are in the same square. In this case the first player wins as the game ends as soon as both chips are in the same square, and the condition of the loss (the inability to move) does not arise.
You know the board sizes and the positions of the two chips on it. At the beginning of the game all board squares are glue-free. Find out who wins if the players play optimally.
Input
The first line contains six integers n, m, x1, y1, x2, y2 — the board sizes and the coordinates of the first and second chips, correspondingly (1 ≤ n, m ≤ 100; 2 ≤ n × m; 1 ≤ x1, x2 ≤ n; 1 ≤ y1, y2 ≤ m). The numbers in the line are separated by single spaces.
It is guaranteed that the chips are located in different squares.
Output
If the first player wins, print "First" without the quotes. Otherwise, print "Second" without the quotes.
Examples
Input
1 6 1 2 1 6
Output
First
Input
6 5 4 3 2 1
Output
First
Input
10 10 1 1 10 10
Output
Second
Submitted Solution:
```
n,m,X,Y,x,y=map(int,input().split())
a=[abs(X-x),abs(Y-y)]
a.sort()
print("First" if a[0]<5 and a[0]+a[1]<7 else "Second")
```
No
| 90,400 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Two players play a game. The game is played on a rectangular board with n × m squares. At the beginning of the game two different squares of the board have two chips. The first player's goal is to shift the chips to the same square. The second player aims to stop the first one with a tube of superglue.
We'll describe the rules of the game in more detail.
The players move in turns. The first player begins.
With every move the first player chooses one of his unglued chips, and shifts it one square to the left, to the right, up or down. It is not allowed to move a chip beyond the board edge. At the beginning of a turn some squares of the board may be covered with a glue. The first player can move the chip to such square, in this case the chip gets tightly glued and cannot move any longer.
At each move the second player selects one of the free squares (which do not contain a chip or a glue) and covers it with superglue. The glue dries long and squares covered with it remain sticky up to the end of the game.
If, after some move of the first player both chips are in the same square, then the first player wins. If the first player cannot make a move (both of his chips are glued), then the second player wins. Note that the situation where the second player cannot make a move is impossible — he can always spread the glue on the square from which the first player has just moved the chip.
We will further clarify the case where both chips are glued and are in the same square. In this case the first player wins as the game ends as soon as both chips are in the same square, and the condition of the loss (the inability to move) does not arise.
You know the board sizes and the positions of the two chips on it. At the beginning of the game all board squares are glue-free. Find out who wins if the players play optimally.
Input
The first line contains six integers n, m, x1, y1, x2, y2 — the board sizes and the coordinates of the first and second chips, correspondingly (1 ≤ n, m ≤ 100; 2 ≤ n × m; 1 ≤ x1, x2 ≤ n; 1 ≤ y1, y2 ≤ m). The numbers in the line are separated by single spaces.
It is guaranteed that the chips are located in different squares.
Output
If the first player wins, print "First" without the quotes. Otherwise, print "Second" without the quotes.
Examples
Input
1 6 1 2 1 6
Output
First
Input
6 5 4 3 2 1
Output
First
Input
10 10 1 1 10 10
Output
Second
Submitted Solution:
```
n,m,x1,y1,x2,y2 = map(int, input().split())
n = abs(x1 - x2)
m = abs(y1 - y2)
if n > 2 or m > 2:
print("Second")
elif n == 2 and m == 2:
print("Second")
else:
print("First")
```
No
| 90,401 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Pavel plays a famous computer game. A player is responsible for a whole country and he can travel there freely, complete quests and earn experience.
This country has n cities connected by m bidirectional roads of different lengths so that it is possible to get from any city to any other one. There are portals in k of these cities. At the beginning of the game all portals are closed. When a player visits a portal city, the portal opens. Strange as it is, one can teleport from an open portal to an open one. The teleportation takes no time and that enables the player to travel quickly between rather remote regions of the country.
At the beginning of the game Pavel is in city number 1. He wants to open all portals as quickly as possible. How much time will he need for that?
Input
The first line contains two space-separated integers n and m (1 ≤ n ≤ 105, 0 ≤ m ≤ 105) that show how many cities and roads are in the game.
Each of the next m lines contains the description of a road as three space-separated integers xi, yi, wi (1 ≤ xi, yi ≤ n, xi ≠ yi, 1 ≤ wi ≤ 109) — the numbers of the cities connected by the i-th road and the time needed to go from one city to the other one by this road. Any two cities are connected by no more than one road. It is guaranteed that we can get from any city to any other one, moving along the roads of the country.
The next line contains integer k (1 ≤ k ≤ n) — the number of portals.
The next line contains k space-separated integers p1, p2, ..., pk — numbers of the cities with installed portals. Each city has no more than one portal.
Output
Print a single number — the minimum time a player needs to open all portals.
Please, do not use the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.
Examples
Input
3 3
1 2 1
1 3 1
2 3 1
3
1 2 3
Output
2
Input
4 3
1 2 1
2 3 5
2 4 10
3
2 3 4
Output
16
Input
4 3
1 2 1000000000
2 3 1000000000
3 4 1000000000
4
1 2 3 4
Output
3000000000
Note
In the second sample the player has to come to city 2, open a portal there, then go to city 3, open a portal there, teleport back to city 2 and finally finish the journey in city 4.
Submitted Solution:
```
print("Hello World!")
print("Hello World!")
print("Hello World!")
```
No
| 90,402 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n=int(input())
arr1=list(map(int,input().split()))
count=0
j=0
arr2=sorted(arr1)
for i in range(n):
if(arr1[i]!=arr2[i]):
count+=1
if(count<=2):
print('YES')
else:
print('NO')
```
| 90,403 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n = int(input())
arr = list(map(int, input().split()))
ideal = sorted(arr)
i = 0
c = 0
f = 1
while i < n:
if arr[i] != ideal[i]:
c += 1
i += 1
if c > 2:
f = 0
break
if f == 1:
print('YES')
else:
print('NO')
# little elephant
```
| 90,404 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
# Target - Expert on CF
# Be Humblefool
import sys
# inf = float("inf")
# sys.setrecursionlimit(10000000)
# abc='abcdefghijklmnopqrstuvwxyz'
# abd={'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}
# mod, MOD = 1000000007, 998244353
# words = {1:'one',2:'two',3:'three',4:'four',5:'five',6:'six',7:'seven',8:'eight',9:'nine',10:'ten',11:'eleven',12:'twelve',13:'thirteen',14:'fourteen',15:'quarter',16:'sixteen',17:'seventeen',18:'eighteen',19:'nineteen',20:'twenty',21:'twenty one',22:'twenty two',23:'twenty three',24:'twenty four',25:'twenty five',26:'twenty six',27:'twenty seven',28:'twenty eight',29:'twenty nine',30:'half'}
# vow=['a','e','i','o','u']
# dx,dy=[-1,1,0,0],[0,0,1,-1]
# import random
# from collections import deque, Counter, OrderedDict,defaultdict
# from heapq import nsmallest, nlargest, heapify,heappop ,heappush, heapreplace
# from math import ceil,floor,log,sqrt,factorial,pi,gcd
# from bisect import bisect,bisect_left,bisect_right,insort,insort_left,insort_right
def get_array(): return list(map(int, sys.stdin.readline().strip().split()))
def get_ints(): return map(int, sys.stdin.readline().strip().split())
def input(): return sys.stdin.readline().strip()
n = int(input())
Arr = get_array()
New = sorted(Arr)
count = 0
for i in range(n):
if Arr[i]!=New[i]:
count+=1
if count<=2:
print('YES')
else:
print('NO')
```
| 90,405 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n=int(input());lt=list(map(int,input().split()))
ltt=sorted(lt)
cnt=sum(lt[i]!=ltt[i] for i in range(n))
if(cnt>2):print('NO');exit(0)
print('YES')
```
| 90,406 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n=int(input())
#n,k=map(int,input().split())
a=list(map(int, input().split()))
b=sorted(a)
f=0
for i in range(n):
if a[i]!=b[i]:
f+=1
if f<=2:
print("YES")
else:
print("NO")
```
| 90,407 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n = int(input())
a = []
b = input()
i = 0
while i < len(b):
to_add = ""
while i < len(b) and b[i] != " ":
to_add += b[i]
i += 1
a.append(int(to_add))
i += 1
two_times = False
first = second = -1
prev = -1
for i in range(1, n):
if a[i] == prev:
second += 1
if a[i] < a[i - 1]:
if first == -1:
first = i - 1
second = i
prev = a[i]
else:
second = i
break
if first == second == -1:
print("YES")
exit()
for i in range(n):
if a[i] > a[second]:
a[i], a[second] = a[second], a[i]
break
for i in range(1, n):
if a[i] < a[i - 1]:
print("NO")
exit()
print("YES")
```
| 90,408 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n = int(input())
A = [int(a) for a in input().split()]
B = A.copy()
B.sort()
c = 0
for i in range(n):
a = A[i]
b = B[i]
if a == b:
continue
else:
c += 1
if c == 0 or c == 2:
print("YES")
else:
print("NO")
```
| 90,409 |
Provide tags and a correct Python 3 solution for this coding contest problem.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Tags: implementation, sortings
Correct Solution:
```
n = int(input())
c = [int(x) for x in input().split(' ')]
d = sorted(c)
v = 0
for i in range(n):
if c[i] != d[i]: v += 1
#print(v)
if v < 3: print('YES')
else: print('NO')
```
| 90,410 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
n, values, wrong = int(input()), [int(i) for i in input().split()], 0
sorted_values = list(sorted(values))
for i in range(n):
if values[i] != sorted_values[i]:
wrong += 1
if wrong > 2:
print("NO")
else:
print("YES")
```
Yes
| 90,411 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
from sys import stdin, stdout
n = int(stdin.readline())
values = list(map(int, stdin.readline().split()))
challengers = []
for i in range(n):
challengers.append(values[i])
challengers.sort()
cnt = 0
for i in range(1, n + 1):
a = challengers.pop()
if a != values[-i]:
for j in range(n, i, -1):
if values[-j] == a:
values[-j], values[-i] = values[-i], values[-j]
break
break
if sorted(values) != values:
stdout.write('NO')
else:
stdout.write('YES')
```
Yes
| 90,412 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
# cook your dish here
n=int(input())
arr=[int(x) for x in input().split()]
li=arr[:]
li.sort()
c=0
for i in range(n):
if(arr[i]!=li[i]):
c+=1
if(c>2):
print("NO")
break
else:
print("YES")
```
Yes
| 90,413 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
tamanho = int(input())
vetor = input()
vetor = vetor.split()
vetor = [int(vetor[i]) for i in range(0, tamanho)]
troca = 0
copia =[vetor[i] for i in range(0, tamanho)]
vetor.sort()
for i in range(0, tamanho):
if (copia[i] != vetor[i]):
troca += 1
#print(troca)
if (troca <= 2):
print("YES")
else:
print("NO")
```
Yes
| 90,414 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
# Author : raj1307 - Raj Singh
# Date : 02.01.2020
from __future__ import division, print_function
import os,sys
from io import BytesIO, IOBase
if sys.version_info[0] < 3:
from __builtin__ import xrange as range
from future_builtins import ascii, filter, hex, map, oct, zip
def ii(): return int(input())
def si(): return input()
def mi(): return map(int,input().strip().split(" "))
def msi(): return map(str,input().strip().split(" "))
def li(): return list(mi())
def dmain():
sys.setrecursionlimit(100000000)
threading.stack_size(40960000)
thread = threading.Thread(target=main)
thread.start()
#from collections import deque, Counter, OrderedDict,defaultdict
#from heapq import nsmallest, nlargest, heapify,heappop ,heappush, heapreplace
#from math import ceil,floor,log,sqrt,factorial
#from bisect import bisect,bisect_left,bisect_right,insort,insort_left,insort_right
#from decimal import *,threading
#from itertools import permutations
abc='abcdefghijklmnopqrstuvwxyz'
abd={'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}
mod=1000000007
#mod=998244353
inf = float("inf")
vow=['a','e','i','o','u']
dx,dy=[-1,1,0,0],[0,0,1,-1]
def getKey(item): return item[1]
def sort2(l):return sorted(l, key=getKey)
def d2(n,m,num):return [[num for x in range(m)] for y in range(n)]
def isPowerOfTwo (x): return (x and (not(x & (x - 1))) )
def decimalToBinary(n): return bin(n).replace("0b","")
def ntl(n):return [int(i) for i in str(n)]
def powerMod(x,y,p):
res = 1
x %= p
while y > 0:
if y&1:
res = (res*x)%p
y = y>>1
x = (x*x)%p
return res
def gcd(x, y):
while y:
x, y = y, x % y
return x
def isPrime(n) : # Check Prime Number or not
if (n <= 1) : return False
if (n <= 3) : return True
if (n % 2 == 0 or n % 3 == 0) : return False
i = 5
while(i * i <= n) :
if (n % i == 0 or n % (i + 2) == 0) :
return False
i = i + 6
return True
def read():
sys.stdin = open('input.txt', 'r')
sys.stdout = open('output.txt', 'w')
def main():
#for _ in range(ii()):
n=ii()
a=li()
a.insert(0,-inf)
a.insert(n+1,inf)
f=0
for i in range(1,n+1):
if a[i-1]<a[i] and a[i]>a[i+1]:
for j in range(i+2,n+1):
if a[j-1]>a[j] and a[j]<a[j+1]:
a[i],a[j]=a[j],a[i]
f=1
break
if f:
break
if sorted(a)==a:
print('YES')
else:
print('NO')
# region fastio
BUFSIZE = 8192
class FastIO(IOBase):
newlines = 0
def __init__(self, file):
self._fd = file.fileno()
self.buffer = BytesIO()
self.writable = "x" in file.mode or "r" not in file.mode
self.write = self.buffer.write if self.writable else None
def read(self):
while True:
b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
if not b:
break
ptr = self.buffer.tell()
self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
self.newlines = 0
return self.buffer.read()
def readline(self):
while self.newlines == 0:
b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
self.newlines = b.count(b"\n") + (not b)
ptr = self.buffer.tell()
self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
self.newlines -= 1
return self.buffer.readline()
def flush(self):
if self.writable:
os.write(self._fd, self.buffer.getvalue())
self.buffer.truncate(0), self.buffer.seek(0)
class IOWrapper(IOBase):
def __init__(self, file):
self.buffer = FastIO(file)
self.flush = self.buffer.flush
self.writable = self.buffer.writable
self.write = lambda s: self.buffer.write(s.encode("ascii"))
self.read = lambda: self.buffer.read().decode("ascii")
self.readline = lambda: self.buffer.readline().decode("ascii")
def print(*args, **kwargs):
"""Prints the values to a stream, or to sys.stdout by default."""
sep, file = kwargs.pop("sep", " "), kwargs.pop("file", sys.stdout)
at_start = True
for x in args:
if not at_start:
file.write(sep)
file.write(str(x))
at_start = False
file.write(kwargs.pop("end", "\n"))
if kwargs.pop("flush", False):
file.flush()
if sys.version_info[0] < 3:
sys.stdin, sys.stdout = FastIO(sys.stdin), FastIO(sys.stdout)
else:
sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")
# endregion
if __name__ == "__main__":
#read()
main()
#dmain()
# Comment Read()
```
No
| 90,415 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
n=int(input())
a=list(map(int,input().split()))
sortedA=sorted(a)
if sortedA==a:
print("YES")
else:
fst=0
snd=0
for i in range(len(a)):
if i+1!=a[i] and fst==0:
fst=i+1
elif i+1!=a[i] and fst!=0:
snd=i
break
fst-=1
a[fst],a[snd]=a[snd],a[fst]
if sortedA==a:
print("YES")
else:
print("NO")
```
No
| 90,416 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
n = int(input())
k = list(map(int,input().split()))
kk = sorted(k)
count = 0
for i in range(n-1):
if k[i] >= k[i+1]:
for j in reversed(range(i+1, n)):
if (k[j] < k[j-1]):
count = 1
k[i],k[j] = k[j],k[i]
break
if count == 1:
break
if k == kk:
print("YES")
else:
print("NO")
```
No
| 90,417 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
The Little Elephant has got a problem — somebody has been touching his sorted by non-decreasing array a of length n and possibly swapped some elements of the array.
The Little Elephant doesn't want to call the police until he understands if he could have accidentally changed the array himself. He thinks that he could have accidentally changed array a, only if array a can be sorted in no more than one operation of swapping elements (not necessarily adjacent). That is, the Little Elephant could have accidentally swapped some two elements.
Help the Little Elephant, determine if he could have accidentally changed the array a, sorted by non-decreasing, himself.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the size of array a. The next line contains n positive integers, separated by single spaces and not exceeding 109, — array a.
Note that the elements of the array are not necessarily distinct numbers.
Output
In a single line print "YES" (without the quotes) if the Little Elephant could have accidentally changed the array himself, and "NO" (without the quotes) otherwise.
Examples
Input
2
1 2
Output
YES
Input
3
3 2 1
Output
YES
Input
4
4 3 2 1
Output
NO
Note
In the first sample the array has already been sorted, so to sort it, we need 0 swap operations, that is not more than 1. Thus, the answer is "YES".
In the second sample we can sort the array if we swap elements 1 and 3, so we need 1 swap operation to sort the array. Thus, the answer is "YES".
In the third sample we can't sort the array in more than one swap operation, so the answer is "NO".
Submitted Solution:
```
n, t = int(input()), list(map(int, input().split()))
s = sum(t[i] < t[i - 1] for i in range(1, n))
print('YES' if s in [0, 2] else 'NO')
```
No
| 90,418 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
from itertools import product
n = int(input().strip())
if n<102:
print(n)
else:
res = set()
combination = (str(i)+str(j) for i in range(10) for j in range(i+1,10))
for it in (product(comb,repeat=l) for comb in combination for l in range(1,len(str(n))+1)):
for line in it:
tmp = int("".join(line))
if tmp and tmp<=n:
res.add(tmp)
print(len(res))
```
| 90,419 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
def p(k):
if 0 < k <= n:
s.add(k)
k *= 10
p(k + x)
p(k + y)
n = int(input())
s = set()
for x in range(10):
for y in range(10):
p(x)
print(len(s))
```
| 90,420 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
# https://codeforces.com/contest/244/problem/B
def gen(digit, x, length, S):
S.append(x)
if length == 10:
return
if len(digit) == 1:
for i in range(0, 10):
next_x = x * 10 + i
if i == digit[0]:
gen(digit, next_x, length+1, S)
else:
gen(digit+[i], next_x, length+1, S)
else:
next_x1 = x * 10 + digit[0]
next_x2 = x * 10 + digit[1]
gen(digit, next_x1, length+1, S)
gen(digit, next_x2, length+1, S)
S = []
for i in range(1, 10):
gen([i], i, 1, S)
S = sorted(S)
x = int(input())
l = -1
u = len(S)
while u-l>1:
md = (u+l) // 2
if x >= S[md]:
l = md
else:
u = md
print(u)
```
| 90,421 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
#CF Round 150. Div II Prob. A - Dividing Orange
import sys
dp = [[[-1 for j in range(3)] for i in range (1 << 10)] for k in range(11)]
In = sys.stdin
n = In.readline().strip()
def go (idx, mask, equal):
if dp[idx][mask][equal] != -1:
return dp[idx][mask][equal]
if bin(mask).count("1") > 2:
return 0
if idx == len(n):
return 1
res = 0
if idx == 0 or equal == 2:
res += go(idx + 1, mask, 2)
elif equal == 1 and int(n[idx]) == 0:
res += go(idx + 1, mask | 1, 1)
else:
res += go(idx + 1, mask | 1, 0)
for i in range(1, 10):
if equal == 1 and i > int(n[idx]):
break
elif equal == 1 and i == int(n[idx]):
res += go(idx + 1, mask | (1 << i), 1)
else:
res += go(idx + 1, mask | (1 << i), 0)
dp[idx][mask][equal] = res
return res
print(go(0, 0, 1) - 1)
```
| 90,422 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
def dfs(k):
if 0 < k <= n:
s.add(k)
k *= 10
dfs(k + x)
dfs(k + y)
n = int(input())
s = set()
for x in range(10):
for y in range(10):
dfs(x)
print(len(s))
```
| 90,423 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
def findNum(num):
if 0 < num <= n:
s.add(num)
num*=10
findNum(num+x)
findNum(num+y)
n = int(input())
s = set()
for x in range(10):
for y in range(10):
findNum(x)
print(len(s))
```
| 90,424 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
n=int(input())
def bruteforce(number):
res=0
liste=[]
while number>0:
integer=number%10
if integer not in liste:
liste.append(integer)
number=number//10
return len(liste)<=2
answer=[0]
def dfs(num):
if (num>0 and num<=n):
answer[0]+=1
for a in range(10):
if bruteforce(num*10+a):
dfs(num*10+a)
for chiffre in range(1,10):
dfs(chiffre)
print(answer[0])
```
| 90,425 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Tags: bitmasks, brute force, dfs and similar
Correct Solution:
```
ii=lambda:int(input())
kk=lambda:map(int, input().split())
ll=lambda:list(kk())
q =[]
s=set()
n=ii()
for x in range(10):
for y in range(10):
q.append(x)
while q:
q2 = []
for item in q:
if item > 0 and item <= n:
s.add(item)
item*=10
q2.append(item+x)
q2.append(item+y)
q=q2
print(len(s))
```
| 90,426 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
#!/usr/bin/python3.6
# -*- coding: utf-8 -*-
# @Time : 2020/12/4 1:44 PM
# @Author : Songtao Li
s = set()
def DFS(x, y, num, max_n):
s.add(num)
num_x = 10 * num + x
num_y = 10 * num + y
if num_x and num_x <= max_n:
DFS(x, y, num_x, max_n)
if num_y and num_y <= max_n:
DFS(x, y, num_y, max_n)
if __name__ == "__main__":
n = int(input())
for i in range(10):
for j in range(i, 10):
DFS(i, j, 0, n)
print(len(s)-1)
```
Yes
| 90,427 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
def cnt(s, p):
ans = 0
if p > s: ans = 0
elif len(p) == len(s):
ans = 1 if len(set(p.lstrip('0'))) <= 2 else 0
elif len(set(p.lstrip('0'))) > 2: ans = 0
elif s[:len(p)] > p:
if len(set(p.lstrip('0'))) == 2:
ans = 2**(len(s)-len(p))
elif len(set(p.lstrip('0'))) == 1:
ans = 1 + 9 * (2**(len(s)-len(p)) - 1)
else:
# ab for all a, b != 0
ans = 10 + 45 * (2**(len(s)-len(p)) - 2)
ans += 36 * sum([2**l-2 for l in range(2,len(s)-len(p))])
else: ans = sum(cnt(s, p+c) for c in '0123456789')
return ans
print(cnt(input().strip(), '')-1)
# Made By Mostafa_Khaled
```
Yes
| 90,428 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
#d=sorted(d,key=lambda x:(len(d[x]),-x)) d=dictionary d={x:set() for x in arr}
#n=int(input())
#n,m,k= map(int, input().split())
import heapq
#for _ in range(int(input())):
#n,k=map(int, input().split())
#input=sys.stdin.buffer.readline
#for _ in range(int(input())):
def dfs(x):
if 0< x <=n :
s.add(x)
x*=10
dfs(x+i)
dfs(x+j)
n=int(input())
#arr = list(map(int, input().split()))
s=set()
for i in range(1,10):
for j in range(10):
dfs(i)
print(len(s))
```
Yes
| 90,429 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
n=int(input())
a=[]
def foo(x,i,j):
if x>n:
return
if x:
a.append(x)
if 10*x+i!=x:
foo(10*x+i,i,j)
foo(10*x+j,i,j)
for i in range(10):
for j in range(i+1,10):
foo(0,i,j)
print(len(set(a)))
```
Yes
| 90,430 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
global ans
ans = 0;
global n
def dfs(num):
global ans
if num > n :
return
a = [0]*10
k = num
while k != 0 :
a[int(k%10)] += 1
k = k / 10
cnt = 0
for i in range(10):
if a[i] > 0 :
cnt += 1
if cnt > 2 :
return
if num > 0 :
ans += 1
for i in range(10):
if i == 0 and num == 0 :
continue
dfs(num*10 + i)
global n
n = int(input())
dfs(0)
print(ans)
```
No
| 90,431 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
from random import randint
n = int(input())
ses = set()
for c1 in range(10):
for c2 in range(c1 + 1, 10):
C = [c1, c2]
for _ in range(4000):
kek = C[randint(0, 1)]
while kek <= n:
ses.add(kek)
kek *= 10; kek += C[randint(0, 1)]
print(len(ses)-1)
```
No
| 90,432 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time
sys.setrecursionlimit(10**7)
inf = 10**9
n = int(input())
if n < 100:
print(n)
sys.exit()
a = [[_,set(map(int,list(str(_))))] for _ in range(100)]
c = 99
for k in range(2,11):
t = (10 ** (k-1))
for aa in a:
if aa[0] >= t:
break
aa[1] |= set([0])
for i in range(1,10):
t = i * (10 ** k)
for ai, ae in a[:]:
ac = ai + t
if ac > n:
print(c)
sys.exit()
if len(ae) < 2:
ae = ae | set([i])
if i in ae:
c += 1
a.append([ac,ae])
```
No
| 90,433 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Polycarpus loves lucky numbers. Everybody knows that lucky numbers are positive integers, whose decimal representation (without leading zeroes) contain only the lucky digits x and y. For example, if x = 4, and y = 7, then numbers 47, 744, 4 are lucky.
Let's call a positive integer a undoubtedly lucky, if there are such digits x and y (0 ≤ x, y ≤ 9), that the decimal representation of number a (without leading zeroes) contains only digits x and y.
Polycarpus has integer n. He wants to know how many positive integers that do not exceed n, are undoubtedly lucky. Help him, count this number.
Input
The first line contains a single integer n (1 ≤ n ≤ 109) — Polycarpus's number.
Output
Print a single integer that says, how many positive integers that do not exceed n are undoubtedly lucky.
Examples
Input
10
Output
10
Input
123
Output
113
Note
In the first test sample all numbers that do not exceed 10 are undoubtedly lucky.
In the second sample numbers 102, 103, 104, 105, 106, 107, 108, 109, 120, 123 are not undoubtedly lucky.
Submitted Solution:
```
from random import randint
n = int(input())
ses = set()
for c1 in range(10):
for c2 in range(c1 + 1, 10):
C = [c1, c2]
for _ in range(4100):
kek = C[randint(0, 1)]
while kek <= n:
ses.add(kek)
kek *= 10; kek += C[randint(0, 1)]
print(len(ses)-1)
```
No
| 90,434 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
from collections import Counter
n, m = map(int, input().split())
g = [[] for _ in range(n)]
for i in range(m):
x, y = map(int, input().split())
g[x - 1].append(y - 1)
g[y - 1].append(x - 1)
bus = ([2] * (n - 2)) + ([1] * 2)
star = [1] * (n - 1) + [n - 1]
lns = [len(lst) for lst in g]
if lns == [2] * n:
print("ring topology")
elif Counter(lns) == Counter(bus):
print("bus topology")
elif Counter(lns) == Counter(star):
print("star topology")
else:
print("unknown topology")
```
| 90,435 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
from collections import defaultdict
I = lambda: map(int, input().split())
degrees = defaultdict(int)
n, m = I()
for _ in range(m):
u, v = I()
degrees[u] += 1
degrees[v] += 1
values = set(degrees.values())
answer = 'unknown'
if values == {2}:
answer = 'ring'
elif values == {1, 2}:
answer = 'bus'
elif values == {1, m}:
answer = 'star'
print(answer, 'topology')
```
| 90,436 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
n, m = map(int, input().split())
graph = {
i: [] for i in range(1, n+1)
}
for i in range(m):
start, end = map(int, input().split())
graph[start].append(end)
graph[end].append(start)
length_array = []
for i in graph:
length_array.append(len(graph[i]))
if min(length_array) == max(length_array) and max(length_array) == 2:
print('ring topology')
elif length_array.count(1) == 2 and length_array.count(2) == n - 2:
print('bus topology')
elif max(length_array) == m and m == n - 1:
print('star topology')
else:
print('unknown topology')
```
| 90,437 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
n, m = [int(i) for i in input().split()]
s = []
for i in range(n + 1):
s.append([])
for i in range(m):
x, y = [int(i) for i in input().split()]
s[x].append(y)
s[y].append(x)
sbool = [False] * (n + 1)
v2 = 0
v1 = 0
other = 0
def dfs(new):
global sbool, s, v2, v1, other
sbool[new] = True
if len(s[new]) == 1:
v1 += 1
elif len(s[new]) == 2:
v2 += 1
else:
other += 1
for i in range(1, n + 1):
dfs(i)
if v1 == 2 and v2 == n - 2:
print('bus topology')
elif v1 == n - 1 and other == 1:
print('star topology')
elif v2 == n:
print('ring topology')
else:
print('unknown topology')
```
| 90,438 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
n, m = [int(i) for i in input().split()]
graf = [[] for i in range(n + 1)]
for i in range(m):
k1, k2 = [int(i) for i in input().split()]
graf[k1].append(k2)
graf[k2].append(k1)
seks = [0, 0, 0]
for i in range(1, n + 1):
if len(graf[i]) == 1 or len(graf[i]) == 2:
seks[len(graf[i])] += 1
else:
seks[0] += 1
if seks[0] == 0 and seks[1] == 2:
print('bus topology')
elif seks[0] == seks[1] == 0:
print('ring topology')
elif seks[0] == 1 and seks[2] == 0:
print('star topology')
else:
print('unknown topology')
```
| 90,439 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
n, m = map(int, input().split())
d = dict()
maxi = 0
maxv = 0
for _ in range(m):
a, b = map(int, input().split())
if a - 1 in d:
d[a - 1] += 1
else:
d[a - 1] = 1
if b - 1 in d:
d[b - 1] += 1
else:
d[b - 1] = 1
if d[a - 1] > maxv:
maxv = d[a - 1]
maxi = a - 1
if d[b - 1] > maxv:
maxv = d[b - 1]
maxi = b - 1
if m + 1 == n:
if maxv == m:
print('star topology')
elif maxv == 2:
print('bus topology')
else:
print('unknown topology')
elif m == n:
if maxv == 2:
print('ring topology')
else:
print('unknown topology')
else:
print('unknown topology')
```
| 90,440 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
n,m = map(int,input().split())
v = []
def chek_star(v):
t = 0
for i in v:
if i != 1:
t+=1
if t == 1:
return True
return False
for i in range(n):
v.append(0)
for i in range(m):
t1,t2 = map(int,input().split())
v[t1-1]+=1
v[t2-1]+=1
if max(v) == 2 and min(v) == 2:
print("ring topology")
elif set(v) == set([1,2]):
print("bus topology")
elif set(v) == set([1,max(v)]) and chek_star(v):
print("star topology")
else:
print("unknown topology")
```
| 90,441 |
Provide tags and a correct Python 3 solution for this coding contest problem.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Tags: graphs, implementation
Correct Solution:
```
# brute force baby
from sys import stdin
node,edge = map(int,input().split())
capt = [0]*node
for l in stdin.readlines():
a,b = map(int,l.split())
capt[a-1] +=1; capt[b-1] += 1
if capt.count(1) == node - 1:
print('star topology')
elif capt.count(2) == node:
print('ring topology')
elif capt.count(1) == 2 and capt.count(2) == node - 2:
print('bus topology')
else:
print('unknown topology')
```
| 90,442 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
from functools import reduce
def add(a,b):
return a+b
n,m = [int(x) for x in input().split()]
neigh = [[] for x in range(n)]
for i in range(m):
x,y = [int(a) for a in input().split()]
neigh[x-1].append(y)
neigh[y-1].append(x)
oneneigh, twoneigh, nneigh = 0,0,0
for i in neigh:
if len(i) == 1:
oneneigh += 1
elif len(i) == 2:
twoneigh += 1
else:
nneigh += 1
if twoneigh == n:
print('ring topology')
elif oneneigh == 2 and twoneigh == n-2:
print('bus topology')
elif nneigh == 1 and oneneigh == m:
print('star topology')
else:
print('unknown topology')
```
Yes
| 90,443 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
n,m = map(int, input().split())
db = [[] for i in range(n)]
for i in range(m):
x,y = map(int, input().split())
db[x-1].append(y)
db[y-1].append(x)
one = 0
two = 0
mx = 0
for i in range(n):
ln = len(db[i])
if ln == 1:
one += 1
elif ln == 2:
two += 1
mx = max(mx,ln)
if one == 2 and two == n-2:
print("bus topology")
elif two == n:
print("ring topology")
elif one == n-1 and mx == n-1:
print("star topology")
else:
print("unknown topology")
```
Yes
| 90,444 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
n,m = map(int, input().split())
adj = [[] for i in range(n+1)]
for i in range(m):
a,b = map(int, input().split())
adj[a].append(b)
adj[b].append(a)
edgeCount = [0]
for i in range(1,n+1):
edgeCount.append(len(adj[i]))
edgeCountCount = [0 for i in range(n+1)]
for i in edgeCount:
edgeCountCount[i] += 1
if edgeCountCount[1] == 2 and edgeCountCount[2] == n-2:
print('bus topology')
elif edgeCountCount[2] == m:
print('ring topology')
elif edgeCountCount[1] == m and edgeCountCount[m] == 1:
print('star topology')
else:
print('unknown topology')
```
Yes
| 90,445 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
n,m=map(int,input().split())
graph={}
for i in range(1,n+1):
graph[i]=[]
for i in range(m):
u,v=map(int,input().split())
graph[u].append(v)
graph[v].append(u)
c=0
d=0
#print(graph)
for i in range(1,n+1):
if len(graph[i])==1:
c=c+1
elif len(graph[i])>=2:
d=d+1
if m==n-1 and c==2 and d==n-2:
print("bus topology")
elif c==0 and d==n and m==n:
print("ring topology")
elif c==n-1 and d==1:
print("star topology")
else:
print("unknown topology")
```
Yes
| 90,446 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
from collections import defaultdict
I = lambda: list(map(int, input().split()))
degrees = defaultdict(int)
for _ in range(I()[1]):
u, v = I()
degrees[u] += 1
degrees[v] += 1
values = set(degrees.values())
if values == {1, 2}:
print('bus topology')
elif values == {2}:
print('ring topology')
elif len(values) == 2 and 1 in values:
print('star topology')
else:
print('unknown topology')
```
No
| 90,447 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
from collections import defaultdict
n, m = map(int, input().split())
h = defaultdict(set)
nums = [0] * n
for i in range(m):
u, v = map(int, input().split())
h[u].add(v)
h[v].add(u)
full = 0
one = 0
two = 0
for key, value in h.items():
if len(value) == n - 1: full += 1
if len(value) == 1: one += 1
if len(value) == 2: two += 1
if full == 1 and full + one == n:
print('star topology')
elif two == n:
print('ring topology')
elif two == n - 2 and one == 2:
print('bus topology')
else:
print('unkown topology')
```
No
| 90,448 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
n, m = [int(i) for i in input().split()]
nodes = []
edges = []
x = 0
for i in range(m):
nums = [int(i) for i in input().split()]
nodes.append(nums[0])
edges.append(nums[1])
if sum(nodes) == len(nodes):
print('star topology')
elif sum(nodes) == sum(edges):
print('ring topology')
elif x == 0:
for i in range(m):
if nodes[i] + 1 == edges[i]:
x += 1
if x == m:
print('bus topology')
else:
print('unknown topology')
```
No
| 90,449 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
This problem uses a simplified network topology model, please read the problem statement carefully and use it as a formal document as you develop the solution.
Polycarpus continues working as a system administrator in a large corporation. The computer network of this corporation consists of n computers, some of them are connected by a cable. The computers are indexed by integers from 1 to n. It's known that any two computers connected by cable directly or through other computers
Polycarpus decided to find out the network's topology. A network topology is the way of describing the network configuration, the scheme that shows the location and the connections of network devices.
Polycarpus knows three main network topologies: bus, ring and star. A bus is the topology that represents a shared cable with all computers connected with it. In the ring topology the cable connects each computer only with two other ones. A star is the topology where all computers of a network are connected to the single central node.
Let's represent each of these network topologies as a connected non-directed graph. A bus is a connected graph that is the only path, that is, the graph where all nodes are connected with two other ones except for some two nodes that are the beginning and the end of the path. A ring is a connected graph, where all nodes are connected with two other ones. A star is a connected graph, where a single central node is singled out and connected with all other nodes. For clarifications, see the picture.
<image> (1) — bus, (2) — ring, (3) — star
You've got a connected non-directed graph that characterizes the computer network in Polycarpus' corporation. Help him find out, which topology type the given network is. If that is impossible to do, say that the network's topology is unknown.
Input
The first line contains two space-separated integers n and m (4 ≤ n ≤ 105; 3 ≤ m ≤ 105) — the number of nodes and edges in the graph, correspondingly. Next m lines contain the description of the graph's edges. The i-th line contains a space-separated pair of integers xi, yi (1 ≤ xi, yi ≤ n) — the numbers of nodes that are connected by the i-the edge.
It is guaranteed that the given graph is connected. There is at most one edge between any two nodes. No edge connects a node with itself.
Output
In a single line print the network topology name of the given graph. If the answer is the bus, print "bus topology" (without the quotes), if the answer is the ring, print "ring topology" (without the quotes), if the answer is the star, print "star topology" (without the quotes). If no answer fits, print "unknown topology" (without the quotes).
Examples
Input
4 3
1 2
2 3
3 4
Output
bus topology
Input
4 4
1 2
2 3
3 4
4 1
Output
ring topology
Input
4 3
1 2
1 3
1 4
Output
star topology
Input
4 4
1 2
2 3
3 1
1 4
Output
unknown topology
Submitted Solution:
```
n, m = map(int, input().split())
s = [set() for _ in range(n+1)]
for _ in range(m):
a, b = map(int, input().split())
s[a].add(b)
s[b].add(a)
x = set()
for i in range(1, n+1):
if len(s[i]) == 1:
x.add(i)
if len(x) == 0:
print("ring topology")
elif x == {1, n}:
print("bus topology")
elif len(x) == m:
print("star topology")
else:
print("unknown topology")
```
No
| 90,450 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
# cf 363 B 1200
n, k = map(int, input().split())
A = [*map(int, input().split())]
wsz = 0
wsum = 0
min_ = float("inf")
mini = 0
for i in range(len(A)):
wsum += A[i]
wsz += 1
if wsz > k:
wsum -= A[1 + i - wsz]
wsz -= 1
if wsum < min_ and wsz == k:
min_ = wsum
mini = 1 + i - wsz
print(1 + mini)
```
| 90,451 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
a,b=map(int,input().split());c=list(map(int,input().split()));s=k=sum(c[:b]);j=0
for i in range(1,a-b+1):
n=s-c[i-1]+c[i+b-1]
if k>n:j=i;k=n
s=n
print(j+1)
```
| 90,452 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
n, k = [int(i) for i in input().split()] #int(input())
arr = [int(i) for i in input().split()]
acc = 0
for i in range(n):
acc += arr[i]
arr[i] = acc
arr = [0] + arr
min_idx = 0
min_br = arr[-1] + 1
for i in range(n-k+1):
if arr[k+i] - arr[i] < min_br:
min_br = arr[k+i] - arr[i]
min_idx = i+1
print(min_idx)
```
| 90,453 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
import os
import sys
from collections import Counter
from io import BytesIO, IOBase
BUFSIZE = 8192
class FastIO(IOBase):
newlines = 0
def __init__(self, file):
self._fd = file.fileno()
self.buffer = BytesIO()
self.writable = "x" in file.mode or "r" not in file.mode
self.write = self.buffer.write if self.writable else None
def read(self):
while True:
b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
if not b:
break
ptr = self.buffer.tell()
self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
self.newlines = 0
return self.buffer.read()
def readline(self):
while self.newlines == 0:
b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
self.newlines = b.count(b"\n") + (not b)
ptr = self.buffer.tell()
self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
self.newlines -= 1
return self.buffer.readline()
def flush(self):
if self.writable:
os.write(self._fd, self.buffer.getvalue())
self.buffer.truncate(0), self.buffer.seek(0)
class IOWrapper(IOBase):
def __init__(self, file):
self.buffer = FastIO(file)
self.flush = self.buffer.flush
self.writable = self.buffer.writable
self.write = lambda s: self.buffer.write(s.encode("ascii"))
self.read = lambda: self.buffer.read().decode("ascii")
self.readline = lambda: self.buffer.readline().decode("ascii")
sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")
def main():
t=1
for _ in range(t):
n,k=map(int,input().split())
a=list(map(int,input().split()))
s=sum(a[:k])
# print(s)
mins=s
idx=0
for i in range(1,n-k+1):
# print('i',i)
s=s-a[i-1]+a[i+k-1]
# print(s)
if(s<mins):
mins=s
idx=i
print(idx+1)
if __name__ == "__main__":
main()
```
| 90,454 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
n,k=map(int,input().split())
l=list(map(int,input().split()))
dp=[0]*(n+1)
for i in range(n):
dp[i+1]=dp[i]+l[i]
mn=999999999
ans=-1
for i in range(k,n+1):
if(dp[i]-dp[i-k]<mn):
mn=dp[i]-dp[i-k]
ans=i-k+1
print(ans)
```
| 90,455 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
n,k = map(int,input().split())
lis = list(map(int,input().split()))
ans=[]
mi=sum(lis[:k])
su=mi
ind=0
for i in range(k,n):
su+=lis[i]
su-=lis[i-k]
if su<mi:
ind=i-k+1
mi=su
print(ind+1)
```
| 90,456 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
n,k=map(int,input().split())
a=list(map(int,input().split()))
c=[0]*len(a)
c[0]=a[0]
for i in range(1,n):
c[i]=c[i-1]+a[i]
mini=c[k-1]
h=1
#print(mini)
for i in range(k,n):
t=mini
#print('i',i)
mini=min(mini,c[i]-c[i-k])
#print(c[i]-c[i-k])
# print(mini)
if mini!=t:
h=i-k+2
print(h)
#print(i)
```
| 90,457 |
Provide tags and a correct Python 3 solution for this coding contest problem.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Tags: brute force, dp
Correct Solution:
```
n,k=map(int,input().split())
l=list(map(int,input().split()))
s=0
d=[0]
for i in l:
s+=i
d.append(s)
prev=float('inf')
idx=-1
for i in range(k-1,n):
s=d[i+1]-d[i-k+1]
#print(i,i-k+1,s,d[i+1],d[i-k+1])
if prev>s:
prev=s
idx=i+1-k+1
print(idx)
```
| 90,458 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
arr=[]
x=input()
xx=x.split(' ')
n=int(xx[0])
k=int(xx[1])
l = 0
t = 15000001
x=input()
xx=x.split(' ')
arr.append(0)
for i in xx:
arr.append(int(i))
for i in range(1,n+1):
arr[i] += arr[i - 1]
for i in range(k,n+1):
if t > arr[i] - arr[i - k]:
t = arr[i] - arr[i - k]
z = i
print(z - k + 1)
```
Yes
| 90,459 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
#from functools import reduce
#mod=int(1e9+7)
#import resource
#resource.setrlimit(resource.RLIMIT_STACK, [0x100000000, resource.RLIM_INFINITY])
#import threading
#threading.stack_size(2**26)
"""fact=[1]
#for i in range(1,100001):
# fact.append((fact[-1]*i)%mod)
#ifact=[0]*100001
#ifact[100000]=pow(fact[100000],mod-2,mod)
#for i in range(100000,0,-1):
# ifact[i-1]=(i*ifact[i])%mod"""
#from collections import deque, defaultdict, Counter, OrderedDict
#from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians, gcd
#from heapq import heappush, heappop, heapify, nlargest, nsmallest
# sys.setrecursionlimit(10**6)
from sys import stdin, stdout
import bisect #c++ upperbound
from bisect import bisect_left as bl #c++ lowerbound bl(array,element)
from bisect import bisect_right as br #c++ upperbound
import itertools
from collections import Counter
from math import sqrt
import collections
import math
import heapq
import re
def modinv(n,p):
return pow(n,p-2,p)
def cin():
return map(int,sin().split())
def ain(): #takes array as input
return list(map(int,sin().split()))
def sin():
return input()
def inin():
return int(input())
def Divisors(n) :
l = []
for i in range(1, int(math.sqrt(n) + 1)) :
if (n % i == 0) :
if (n // i == i) :
l.append(i)
else :
l.append(i)
l.append(n//i)
return l
def most_frequent(list):
return max(set(list), key = list.count)
def GCD(x,y):
while(y):
x, y = y, x % y
return x
def ncr(n,r,p): #To use this, Uncomment 19-25
t=((fact[n])*((ifact[r]*ifact[n-r])%p))%p
return t
def Convert(string):
li = list(string.split(""))
return li
def SieveOfEratosthenes(n):
global prime
prime = [True for i in range(n+1)]
p = 2
while (p * p <= n):
if (prime[p] == True):
for i in range(p * p, n+1, p):
prime[i] = False
p += 1
f=[]
for p in range(2, n):
if prime[p]:
f.append(p)
return f
prime=[]
q=[]
def dfs(n,d,v,c):
global q
v[n]=1
x=d[n]
q.append(n)
j=c
for i in x:
if i not in v:
f=dfs(i,d,v,c+1)
j=max(j,f)
# print(f)
return j
#Implement heapq
#grades = [110, 25, 38, 49, 20, 95, 33, 87, 80, 90]
#print(heapq.nlargest(3, grades)) #top 3 largest
#print(heapq.nsmallest(4, grades))
#Always make a variable of predefined function for ex- fn=len
#n,k=map(int,input().split())
"""*******************************************************"""
def main():
n,k = map(int,input().split())
f = list(map(int,input().split()))
s = sum(f[:k])
best =s
j = 1
for i in range(n-k):
s-=f[i]
s+=f[k+i]
if s<best:
best = s
j = i+2
print(j)
"""*******************************************************"""
######## Python 2 and 3 footer by Pajenegod and c1729
py2 = round(0.5)
if py2:
from future_builtins import ascii, filter, hex, map, oct, zip
range = xrange
import os, sys
from io import IOBase, BytesIO
BUFSIZE = 8192
class FastIO(BytesIO):
newlines = 0
def __init__(self, file):
self._file = file
self._fd = file.fileno()
self.writable = "x" in file.mode or "w" in file.mode
self.write = super(FastIO, self).write if self.writable else None
def _fill(self):
s = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
self.seek((self.tell(), self.seek(0,2), super(FastIO, self).write(s))[0])
return s
def read(self):
while self._fill(): pass
return super(FastIO,self).read()
def readline(self):
while self.newlines == 0:
s = self._fill(); self.newlines = s.count(b"\n") + (not s)
self.newlines -= 1
return super(FastIO, self).readline()
def flush(self):
if self.writable:
os.write(self._fd, self.getvalue())
self.truncate(0), self.seek(0)
class IOWrapper(IOBase):
def __init__(self, file):
self.buffer = FastIO(file)
self.flush = self.buffer.flush
self.writable = self.buffer.writable
if py2:
self.write = self.buffer.write
self.read = self.buffer.read
self.readline = self.buffer.readline
else:
self.write = lambda s:self.buffer.write(s.encode('ascii'))
self.read = lambda:self.buffer.read().decode('ascii')
self.readline = lambda:self.buffer.readline().decode('ascii')
sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip('\r\n')
if __name__== "__main__":
main()
#threading.Thread(target=main).start()
```
Yes
| 90,460 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
n,m=map(int,input().strip().split())
arr=list(map(int,input().strip().split()))
s=sum(arr[0:m])
minimum=s
index=0
for i in range(m, n):
s = s - arr[i - m] + arr[i]
if s<minimum:
minimum=s
index = i - m + 1
print(index + 1)
```
Yes
| 90,461 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
def func():
n, k = map(int, input().split())
arr = list(map(int, input().split()))
min_possible = k
curr_sum = sum(arr[:k])
min_sum = float("inf")
index = None
for i in range(k, n):
if curr_sum == min_possible:
return i - k + 1
if curr_sum < min_sum:
index = i - k + 1
min_sum = curr_sum
curr_sum += arr[i] - arr[i-k]
if curr_sum < min_sum:
return n - k + 1
return index
print(func())
```
Yes
| 90,462 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
# -*- coding: utf-8 -*-
"""
Created on Tue Mar 12 18:07:43 2019
@author: avina
"""
n,l = map(int, input().strip().split())
L = list(map(int, input().strip().split()))
s = sum(L[:l])
m = s
k = l - 1
for i in range(l,n-l+1):
s-= L[i-l] - L[i]
if s<m:
k = i
m = s
print(k+2 - l)
```
No
| 90,463 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
x,y=map(int,input().split())
a=list(map(int,input().split()))
for i in range(1,x):
a[i]+=a[i-1]
s=1000000
p=-1
for i in range(y+1,x):
if s>=a[i]-a[i-y-1]:
s=a[i]-a[i-y-1]
p=i-y
p=1 if p==-1 else p
print(p)
```
No
| 90,464 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
n,k=map(int,input().split())
l=list(map(int,input().split()))
s=[11**11,sum(l[0:k])]
for i in range(1,n-k):
s+=[s[-1]-l[i-1]+l[i+k-1]]
print(s.index(min(s)))
```
No
| 90,465 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
There is a fence in front of Polycarpus's home. The fence consists of n planks of the same width which go one after another from left to right. The height of the i-th plank is hi meters, distinct planks can have distinct heights.
<image> Fence for n = 7 and h = [1, 2, 6, 1, 1, 7, 1]
Polycarpus has bought a posh piano and is thinking about how to get it into the house. In order to carry out his plan, he needs to take exactly k consecutive planks from the fence. Higher planks are harder to tear off the fence, so Polycarpus wants to find such k consecutive planks that the sum of their heights is minimal possible.
Write the program that finds the indexes of k consecutive planks with minimal total height. Pay attention, the fence is not around Polycarpus's home, it is in front of home (in other words, the fence isn't cyclic).
Input
The first line of the input contains integers n and k (1 ≤ n ≤ 1.5·105, 1 ≤ k ≤ n) — the number of planks in the fence and the width of the hole for the piano. The second line contains the sequence of integers h1, h2, ..., hn (1 ≤ hi ≤ 100), where hi is the height of the i-th plank of the fence.
Output
Print such integer j that the sum of the heights of planks j, j + 1, ..., j + k - 1 is the minimum possible. If there are multiple such j's, print any of them.
Examples
Input
7 3
1 2 6 1 1 7 1
Output
3
Note
In the sample, your task is to find three consecutive planks with the minimum sum of heights. In the given case three planks with indexes 3, 4 and 5 have the required attribute, their total height is 8.
Submitted Solution:
```
n, k = [int(i) for i in input().split(" ")]
A = [int(i) for i in input().split(" ")]
cons = [A[0]]
for i in range(1, len(A)):
cons.append(cons[-1] + A[i])
a = []
Min = 999999
ans = 0
i = 0
j = k
while j < n:
a.append(cons[j] - cons[i])
if cons[j] - cons[i] < Min:
Min = cons[j] - cons[i]
ans = i
j += 1
i += 1
print(i + 2)
```
No
| 90,466 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
from sys import stdin
from datetime import datetime, timedelta
def main():
s = stdin.readline().strip()
t = stdin.readline().strip()
s = datetime.strptime(s, '%H:%M')
t = datetime.strptime(t, '%H:%M')
t = timedelta(hours = t.hour, minutes = t.minute)
p = s - t
print('{:02}:{:02}'.format(p.hour, p.minute))
if __name__ == '__main__': main()
```
| 90,467 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
# ///==========Libraries, Constants and Functions=============///
#mkraghav
import sys
inf = float("inf")
mod = 1000000007
def get_array(): return list(map(int, sys.stdin.readline().split()))
def get_ints(): return map(int, sys.stdin.readline().split())
def input(): return sys.stdin.readline()
def int1():return int(input())
import string
import math
from itertools import combinations
# ///==========MAIN=============///
def main():
s1=input()
s2=input()
x1=int(s1[:2])
x2=int(s1[3:])
y1=int(s2[:2])
y2=int(s2[3:])
x3=x1-y1
y=x2-y2
if y<0:
y=60+y
x3=x3-1
if x3<0:
x3=24+x3
if x3<10:
x3=str(0)+str(x3)
if y<10:
y=str(0)+str(y)
print(str(x3)+':'+str(y))
if __name__ == "__main__":
main()
```
| 90,468 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
wu = input()
t = input()
a = wu.split(':')
b = t.split(':')
resHr = int(a[0]) - int(b[0])
resMin = int(a[1]) - int(b[1])
if int(resMin) < 0:
resMin = str(int(resMin) % 60)
resHr = str(int(resHr) - 1)
else:
resMin = str(resMin)
if int(resHr) < 0:
resHr = str(int(resHr) % 24)
else:
resHr = str(resHr)
if int(resHr) < 10:
resHr = '0'+str(abs(int(resHr)))
else:
resHr = str(resHr)
if abs(int(resMin)) < 10:
resMin = '0'+str(abs(int(resMin)))
else:
resMin = str(resMin)
print(resHr+':'+resMin)
```
| 90,469 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
a=input()
b=input()
c=a.split(":")
d=b.split(":")
currenttime1=int (c[0])
if int(c[0][0])==0 :
currenttime1=int(c[0][1])
currenttime2= int (c[1])
if int(c[-1][0])==0 :
currenttime2=int(c[1][1])
duration1=int(d[0])
if int(d[0][0])==0 :
duration1=int(d[0][1])
duration2=int(d[1])
if int(d[-1][0])==0 :
duration=int(d[1][1])
time2 = currenttime2-duration2
if currenttime2<duration2:
time2= 60 - (duration2-currenttime2)
duration1= duration1+1
time =currenttime1-duration1
if currenttime1 < duration1:
time = 24 - (duration1-currenttime1)
if time <=9 :
time='0'+ str(time)
if time2 <=9 :
time2='0'+ str(time2)
print(str(time)+':'+str(time2))
```
| 90,470 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
s, t = (tuple(map(int, input().split(':'))) for i in "01")
z = ((s[0], 24)[not s[0]] - t[0]) * 60 + s[1] - t[1]
print('{:02}:{:02}'.format((z // 60) % 24, z % 60))
```
| 90,471 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
s=input().split(':')
s[0]=int(s[0])
s[1]=int(s[1])
t=input().split(':')
t[0]=int(t[0])
t[1]=int(t[1])
def v(n):
n=str(n)
if len(n)==1:
return '0'+n
else:
return n
if s[0]>=t[0] and s[1]>=t[1]:
print(v(s[0]-t[0])+':'+v(s[1]-t[1]))
elif s[0]>t[0] and s[1]<t[1]:
print(v(s[0]-t[0]-1)+':'+v(s[1]+60-t[1]))
elif s[0]==t[0] and s[1]<t[1]:
print('23'+':'+v(s[1]+60-t[1]))
elif s[0]<t[0] and s[1]>=t[1]:
print(v(24-(t[0]-s[0]))+':'+v(s[1]-t[1]))
elif s[0]<t[0] and s[1]<t[1]:
print(v(24-(t[0]-s[0])-1)+':'+v(60+s[1]-t[1]))
```
| 90,472 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
def func(s):
a, b = list(map(int, s.split(":")))
return a*60+b
ct = func(input())
ts = func(input())
ans = ct - ts
if ans < 0:
ans += 60*24
print("%02i:%02i" % (ans//60, ans%60))
```
| 90,473 |
Provide tags and a correct Python 3 solution for this coding contest problem.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Tags: implementation
Correct Solution:
```
a,b = map(int, input().split(":"))
c, d = map(int, input().split(":"))
a1, a2 = [0]*2
if b< d:
a2 = b - d + 60
if a:
a -= 1
else:
a = 23
else:
a2= b - d
if a < c:
a1 = a - c + 24
else:
a1 = a - c
a1 = str(a1)
a2 =str(a2)
if len(a1) != 2:
a1 = "0" + a1
if len(a2) != 2:
a2 = "0" + a2
print(a1, a2, sep = ":")
```
| 90,474 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
s = [int(x) for x in input().split(":")]
t = [int(x) for x in input().split(":")]
s1 = s[0] * 60 + s[1] + 1440
t1 = t[0] * 60 + t[1]
p = (s1 - t1) % 1440
print("0" * (2 - len(str(p // 60))) + str(p // 60) + ":" + "0" * (2 - len(str(p % 60))) + str(p % 60))
```
Yes
| 90,475 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
s = list(map(int, input().split(':')))
t = list(map(int, input().split(':')))
p = [0, 0]
if s[0] - t[0] < 0:
p[0] = 24 - (t[0] - s[0])
else:
p[0] = s[0] - t[0]
if s[1] - t[1] < 0:
p[1] = 60 - (t[1] - s[1])
if p[0] == 0:
p[0] = 23
else:
p[0] -= 1
else:
p[1] = s[1] - t[1]
if p[0] < 10:
print('0', p[0], sep = '', end = ':')
else:
print(p[0], end = ':')
if p[1] < 10:
print('0', p[1], sep = '')
else:
print(p[1])
```
Yes
| 90,476 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
h1,m1=map(int,input().split(':'))
h2,m2=map(int,input().split(':'))
if h1 == 00:
h1=24
if h2 == 00:
h2=24
time1=h1*60+m1
time2=h2*60+m2
if time2>time1:
time1+=24*60
timex=time1-time2
hx=timex//60
mx=timex%60
if hx<10 :
hx='0'+str(hx)
if mx<10 :
mx='0'+str(mx)
print(hx,end='')
print(':',end='')
print(mx,end='')
```
Yes
| 90,477 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
bangun = input().split(":")
lama_tidur = input().split(":")
menit = int(bangun[1]) - int(lama_tidur[1])
jam = int(bangun[0]) - int(lama_tidur[0])
if menit < 0:
menit += 60
jam -= 1
if jam < 0:
jam += 24
A = str(menit)
B = str(jam)
if len(A) < 2:
A = "0"+A
if len(B)<2:
B = "0"+B
print(B+":"+A)
```
Yes
| 90,478 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
a=input()
b=input()
c=a.split(":")
d=b.split(":")
currenttime1=int (c[0])
if int(c[0][0])==0 :
currenttime1=int(c[0][1])
currenttime2= int (c[1])
if int(c[-1][0])==0 :
currenttime2=int(c[1][1])
duration1=int(d[0])
if int(c[0][0])==0 :
duration1=int(d[0][1])
duration2=int(d[1])
if int(c[-1][0])==0 :
duration=int(d[1][1])
time =currenttime1-duration1
if currenttime1<duration1:
time = 24 - duration1
time2 = currenttime2-duration2
if currenttime2<duration2:
time2= 60 - duration2
if time == 0 :
time= 24 - 1
else:
time= time -1
if time <=9 :
time='0'+ str(time)
if time2 <=9 :
time2='0'+ str(time2)
print(str(time)+':'+str(time2))
```
No
| 90,479 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
s=input()
t=input()
cth=sth=ctm=stm=''
for i in range(0,5):
if i<2:
cth+=s[i]
sth+=t[i]
elif i>2:
ctm += s[i]
stm+=t[i]
ah=int(cth)-int(sth)
am=int(ctm)-int(stm)
if ah>0 and am!=0:
ah=ah-1
if cth==sth and ctm<stm:
ah=23
if ah<0 and am>=0:
ah=24+ah
if ah<0 and am<0:
ah=23+ah
if am<0:
am=60+am
if len(str(ah))==1 and len(str(am))==1:
print("0",ah,":","0",am,sep='')
elif len(str(ah))==1 and len(str(am))==2:
print("0",ah,":",am,sep='')
elif len(str(ah))==2 and len(str(am))==1:
print(ah,":","0",am,sep='')
else:
print(ah,":",am,sep='')
```
No
| 90,480 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
a = input()
q1, q2, q3, q4 = int(a[0]), int(a[1]), int(a[3]), int(a[4])
b = input()
w1, w2, w3, w4 = int(b[0]), int(b[1]), int(b[3]), int(b[4])
ww = (q3*10 + q4) + (q1*10 + q2)*60
qq = (w3*10 + w4) + (w1*10 + w2)*60
s = ""
if q1 == q2 and q3 == q2 and q3 == q4 and w1== q1 and w2 == q1 and w3 == q1 and w4 == q1:
print("00:00")
elif (ww - qq) > 0:
if(ww - qq) // 60 > 9:
d = str((ww - qq)//60)
s += d
else:
s += "0"
d = str((ww - qq)//60)
s += d
s += ":"
if (ww - qq) % 60 > 9:
d = str((ww - qq)%60)
s += d
else:
s += "0"
d = str((ww - qq)%60)
s += d
print(s)
else:
if(ww - qq + 1440) // 60 > 9:
d = str((ww - qq+ 1440)//60)
s += d
else:
s += "0"
d = str((ww - qq+ 1440)//60)
s += d
s += ":"
if (ww - qq + 1440) % 60 > 9:
d = str((ww - qq + 1440)%60)
s += d
else:
s += "0"
d = str((ww - qq + 1440)%60)
s += d
print(s)
```
No
| 90,481 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
George woke up and saw the current time s on the digital clock. Besides, George knows that he has slept for time t.
Help George! Write a program that will, given time s and t, determine the time p when George went to bed. Note that George could have gone to bed yesterday relatively to the current time (see the second test sample).
Input
The first line contains current time s as a string in the format "hh:mm". The second line contains time t in the format "hh:mm" — the duration of George's sleep. It is guaranteed that the input contains the correct time in the 24-hour format, that is, 00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59.
Output
In the single line print time p — the time George went to bed in the format similar to the format of the time in the input.
Examples
Input
05:50
05:44
Output
00:06
Input
00:00
01:00
Output
23:00
Input
00:01
00:00
Output
00:01
Note
In the first sample George went to bed at "00:06". Note that you should print the time only in the format "00:06". That's why answers "0:06", "00:6" and others will be considered incorrect.
In the second sample, George went to bed yesterday.
In the third sample, George didn't do to bed at all.
Submitted Solution:
```
while True:
current = input().split(":")
duration = input().split(":")
if len(current) == 2 and len(duration) == 2:
break
jam = 0
menit = 0
jam = int(current[0]) - int(duration[0])
menit = int(current[1]) - int(duration[1])
if int(current[1]) + int(duration[1]) >= 60:
jam -= 1
if jam < 0:
jam = 24 + jam
if menit < 0:
menit = 60 + menit
if 0 <= jam < 10:
jam = "0" + str(jam)
if 0 <= menit < 10:
menit = "0" + str(menit)
print(str(jam) + ":" + str(menit))
```
No
| 90,482 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Tags: greedy
Correct Solution:
```
import sys
n,m=map(int,sys.stdin.readline().split())
A=list(map(int,sys.stdin.readline().split()))
B=list(map(int,sys.stdin.readline().split()))
A.sort(reverse=True)
B.sort(reverse=True)
a=sum(A)
b=sum(B)
ans=0
left=0
for i in range(n):
left+=A[i]
temp=b*(i+1)+a-left
if(ans==0):
ans=temp
ans=min(ans,temp)
left=0
for i in range(m):
left+=B[i]
temp=a*(i+1)+b-left
if(ans==0):
ans=temp
ans=min(ans,temp)
print(ans)
# Made By Mostafa_Khaled
```
| 90,483 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Tags: greedy
Correct Solution:
```
n, m = list(map(int, input().split()))
A = list(map(int, input().split()))
B = list(map(int, input().split()))
A.sort(reverse=True)
B.sort(reverse=True)
sumA = sum(A)
sumB = sum(B)
ansA = sumB
ansB = sumA
for i in range(1, n):
ansA += min(A[i],sumB)
for i in range(1, m):
ansB += min(B[i], sumA)
print(min(ansA,ansB))
```
| 90,484 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Tags: greedy
Correct Solution:
```
n,m=map(int,input().split())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
# asum=0
# bsum=0
a.sort()
b.sort()
asum=sum(a)
bsum=sum(b)
ans=9999999999999999999999999999999999999999
# print(a[0])
le=0
for i in range(0,n):
tmp=le+(n-i)*(bsum)
ans=min(ans,tmp)
le=le+a[i]
le=0
for i in range(0,m):
tmp=le+(m-i)*(asum)
ans=min(ans,tmp)
le=le+b[i]
print(ans)
```
| 90,485 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Submitted Solution:
```
[n,m]=[int(i) for i in input().split()]
a=[int(i) for i in input().split()]
b=[int(i) for i in input().split()]
sum1=sum(a);sum2=sum(b)
max1=max(a);max2=max(b)
ans=min(sum1+sum2-max2,sum1*m,sum1+sum2-max1,sum2*n)
print(ans)
```
No
| 90,486 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Submitted Solution:
```
mn = [int(i) for i in input().split()]
a = [int(j) for j in input().split()]
b = [int(k) for k in input().split()]
c = a+b
print(c.count(max(c))*(sum(c)-(c.count(max(c))*max(c))))
```
No
| 90,487 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Submitted Solution:
```
[n,m]=[int(i) for i in input().split()]
a=[int(i) for i in input().split()]
b=[int(i) for i in input().split()]
sum1=sum(a);sum2=sum(b)
max1=max(a);max2=max(b)
if sum1<sum2:
ans=min(sum1+sum2-max2,sum1*m)
else:
ans=min(sum2+sum1-max1,sum2*n)
print(ans)
```
No
| 90,488 |
Evaluate the correctness of the submitted Python 3 solution to the coding contest problem. Provide a "Yes" or "No" response.
Piegirl was asked to implement two table join operation for distributed database system, minimizing the network traffic.
Suppose she wants to join two tables, A and B. Each of them has certain number of rows which are distributed on different number of partitions. Table A is distributed on the first cluster consisting of m partitions. Partition with index i has ai rows from A. Similarly, second cluster containing table B has n partitions, i-th one having bi rows from B.
In one network operation she can copy one row from any partition to any other partition. At the end, for each row from A and each row from B there should be a partition that has both rows. Determine the minimal number of network operations to achieve this.
Input
First line contains two integer numbers, m and n (1 ≤ m, n ≤ 105). Second line contains description of the first cluster with m space separated integers, ai (1 ≤ ai ≤ 109). Similarly, third line describes second cluster with n space separated integers, bi (1 ≤ bi ≤ 109).
Output
Print one integer — minimal number of copy operations.
Examples
Input
2 2
2 6
3 100
Output
11
Input
2 3
10 10
1 1 1
Output
6
Note
In the first example it makes sense to move all the rows to the second partition of the second cluster which is achieved in 2 + 6 + 3 = 11 operations
In the second example Piegirl can copy each row from B to the both partitions of the first cluster which needs 2·3 = 6 copy operations.
Submitted Solution:
```
[n,m]=[int(i) for i in input().split()]
a=[int(i) for i in input().split()]
b=[int(i) for i in input().split()]
sum1=sum(a);sum2=sum(b)
max1=max(a);max2=max(b)
ans=min(sum1+sum2-max2,sum1*m,sum1+sum2-max2,sum2*n)
print(ans)
```
No
| 90,489 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
import sys
input=sys.stdin.readline
def solve(n,st,k):
mod=10**9+7
dp=[0]*(n+1)
pre=[0]*(n+1)
dp[st]=1
for t in range(k):
pre[0]=0
for i in range(1,n+1):
pre[i]=pre[i-1]+dp[i]
pre[i]%=mod
for i in range(1,n+1):
dp[i]=(pre[n]-pre[i]+pre[i-1]-pre[i>>1])%mod
return sum(dp)%mod
n,a,b,k=map(int,input().split())
mod=10**9+7
if a>b:
print(solve(n-b,a-b,k))
else:
print(solve(b-1,b-a,k))
```
| 90,490 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
def solve(n, st, k):
MOD = int(1e9 + 7)
dp = [0] * (n + 1)
prefix_sum = [0] * (n + 1)
dp[st] = 1
for times in range(k):
prefix_sum[0] = 0
for i in range(1, n + 1):
prefix_sum[i] = prefix_sum[i - 1] + dp[i]
if prefix_sum[i] >= MOD: prefix_sum[i] -= MOD
for i in range(1, n + 1):
dp[i] = prefix_sum[n] - prefix_sum[i] + prefix_sum[i - 1] - prefix_sum[i >> 1]
while dp[i] < 0: dp[i] += MOD
while dp[i] >= MOD: dp[i] -= MOD
return sum(dp) % MOD
def main():
n, a, b, k = [int(i) for i in input().split()]
if a > b:
print(solve(n - b, a - b, k))
else:
print(solve(b - 1, b - a, k))
main()
```
| 90,491 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
def solve(n, st, k):
MOD = int(1e9 + 7)
prev = [0] * (n + 1)
current = [0] * (n + 1)
prefix_sum = [0] * (n + 1)
prev[st] = 1
for times in range(k):
prefix_sum[0] = 0
for i in range(1, n + 1):
prefix_sum[i] = prefix_sum[i - 1] + prev[i]
if prefix_sum[i] >= MOD:
prefix_sum[i] -= MOD
for i in range(1, n + 1):
current[i] = prefix_sum[n] - prefix_sum[i >> 1] - prev[i]
while current[i] < 0: current[i] += MOD
while current[i] >= MOD: current[i] -= MOD
prev, current = current, prev
return sum(prev) % MOD
def main():
n, a, b, k = [int(i) for i in input().split()]
if a > b:
print(solve(n - b, a - b, k))
else:
print(solve(b - 1, b - a, k))
main()
```
| 90,492 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
#!/usr/bin/env python3
import io
import os
import sys
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline
def printd(*args, **kwargs):
#print(*args, **kwargs, file=sys.stderr)
#print(*args, **kwargs)
pass
def get_str():
return input().decode().strip()
def rint():
return map(int, input().split())
def oint():
return int(input())
mod = 1000000007
n, a, b, k = rint()
if a > b:
a, b = n-a+1, n-b+1
a -= 1
b -= 1
printd(n, a, b, k)
d = [0]*n
d[a] = 1
ps = [0]*b
ps[0] = d[0]
for j in range(1, b):
ps[j] = ps[j-1]+d[j]
ps[j] %= mod
printd(n, a, b, k)
printd(d, ps)
for i in range(k):
for j in range(b):
#b-t > t-j
#2*t < b+j
#t < (b+j)/2
if (b+j)%2:
t = (b+j)//2
else:
t = (b+j)//2 - 1
if j == 0:
d[j] = ps[t] - ps[j]
else:
d[j] = ps[t] - ps[j] + ps[j-1]
d[j] %= mod
#d[j] %=mod
ps[0] = d[0]
for j in range(1, b):
ps[j] = (ps[j-1]+d[j])# %mod
ps[j] %= mod
printd(d,ps)
ans = ps[b-1]
print(ans%mod)
```
| 90,493 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
from sys import stdin
#parser
def parser():
return map(int, stdin.readline().split())
#Guardando el valor de 10^9+7
div=pow(10,9)+7
#Recibiendo los valores de n,a,b,k de la entrada
n,a,b,k=parser()
#Actualizando los valores de a,b y n
if a>b:
a=n-a+1
n=n-b
b=n+1
else:
n=b-1
#Lista para ir guardando las sumas parciales
prefix_sum=[0 for x in range(n+1)]
#Lista para ir guandando los valores d(i,j)
secuences=[0 for x in range(n+1)]
secuences[a]=1
for i in range(k):
#0 piso ficticio que se usa como comodín
prefix_sum[0]=secuences[0]
#Calculando los valores de las sumas parciales
for j in range(1,n+1):
prefix_sum[j]=prefix_sum[j-1]+secuences[j]
prefix_sum[j]%=div
#Calculando los nuevos valores de ''secuences''
for j in range(1,n+1):
distance=b-j
mid_distance=0
#distancia necesaria entre el piso j y un piso de mayor numeracion que el j
if distance % 2 == 0:
mid_distance=distance//2-1
else:
mid_distance=distance//2
#prefix_sum[j-1] es la cantidad de formas de alcanzar el piso j por uno de menor numeracion
#prefix_sum[j+mid_distance]-prefix_sum[j] es la cantidad de formas de alcanzar el piso j por un piso de mayor numeracion
secuences[j]=prefix_sum[j-1]+prefix_sum[j+mid_distance]-prefix_sum[j]
secuences[j]%=div
#Imprimiendo el resultado
print(sum(secuences)%div)
```
| 90,494 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
def solve(n, st, k):
MOD = int(1e9 + 7)
dp = [0] * (n + 1)
prefix_sum = [0] * (n + 1)
dp[st] = 1
for times in range(k):
prefix_sum[0] = 0
for i in range(1, n + 1):
prefix_sum[i] = prefix_sum[i - 1] + dp[i]
if prefix_sum[i] >= MOD: prefix_sum[i] -= MOD
for i in range(1, n + 1):
dp[i] = prefix_sum[n] - dp[i] - prefix_sum[i >> 1]
while dp[i] < 0: dp[i] += MOD
while dp[i] >= MOD: dp[i] -= MOD
return sum(dp) % MOD
def main():
n, a, b, k = [int(i) for i in input().split()]
if a > b:
print(solve(n - b, a - b, k))
else:
print(solve(b - 1, b - a, k))
main()
```
| 90,495 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
#!/usr/bin/env python3
import io
import os
import sys
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline
def printd(*args, **kwargs):
#print(*args, **kwargs, file=sys.stderr)
#print(*args, **kwargs)
pass
def get_str():
return input().decode().strip()
def rint():
return map(int, input().split())
def oint():
return int(input())
mod = 1000000007
n, a, b, k = rint()
if a > b:
a, b = n-a+1, n-b+1
a -= 1
b -= 1
printd(n, a, b, k)
d = [0]*n
d[a] = 1
ps = [0]*b
ps[0] = d[0]
for j in range(1, b):
ps[j] = ps[j-1]+d[j]
while ps[j] > mod:
ps[j] -= mod
printd(n, a, b, k)
printd(d, ps)
for i in range(k):
for j in range(b):
#b-t > t-j
#2*t < b+j
#t < (b+j)/2
if (b+j)%2:
t = (b+j)//2
else:
t = (b+j)//2 - 1
if j == 0:
d[j] = ps[t] - ps[j]
else:
d[j] = ps[t] - ps[j] + ps[j-1]
while d[j] > mod:
d[j] -= mod
while d[j] <0:
d[j] += mod
#d[j] %=mod
ps[0] = d[0]
for j in range(1, b):
ps[j] = (ps[j-1]+d[j])# %mod
while ps[j] > mod:
ps[j] -= mod
while ps[j] < 0:
ps[j] += mod
printd(d,ps)
ans = ps[b-1]
print(ans%mod)
```
| 90,496 |
Provide tags and a correct Python 3 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
#!/usr/bin/env python3
import io
import os
import sys
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline
def printd(*args, **kwargs):
#print(*args, **kwargs, file=sys.stderr)
#print(*args, **kwargs)
pass
def get_str():
return input().decode().strip()
def rint():
return map(int, input().split())
def oint():
return int(input())
mod = 1000000007
n, a, b, k = rint()
if a > b:
a, b = n-a+1, n-b+1
a -= 1
b -= 1
printd(n, a, b, k)
d = [0]*n
d[a] = 1
ps = [0]*b
ps[0] = d[0]
for j in range(1, b):
ps[j] = ps[j-1]+d[j]
while ps[j] > mod:
ps[j] -= mod
ps[j] %= mod
printd(n, a, b, k)
printd(d, ps)
for i in range(k):
for j in range(b):
#b-t > t-j
#2*t < b+j
#t < (b+j)/2
if (b+j)%2:
t = (b+j)//2
else:
t = (b+j)//2 - 1
if j == 0:
d[j] = ps[t] - ps[j]
else:
d[j] = ps[t] - ps[j] + ps[j-1]
while d[j] > mod:
d[j] -= mod
while d[j] <0:
d[j] += mod
d[j] %= mod
#d[j] %=mod
ps[0] = d[0]
for j in range(1, b):
ps[j] = (ps[j-1]+d[j])# %mod
while ps[j] > mod:
ps[j] -= mod
while ps[j] < 0:
ps[j] += mod
ps[j] %= mod
printd(d,ps)
ans = ps[b-1]
print(ans%mod)
```
| 90,497 |
Provide tags and a correct Python 2 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
from sys import stdin, stdout
from collections import Counter, defaultdict
from itertools import permutations, combinations
raw_input = stdin.readline
pr = stdout.write
def in_num():
return int(raw_input())
def in_arr():
return map(int,raw_input().split())
def pr_num(n):
stdout.write(str(n)+'\n')
def pr_arr(arr):
pr(' '.join(map(str,arr))+'\n')
# fast read function for total integer input
def inp():
# this function returns whole input of
# space/line seperated integers
# Use Ctrl+D to flush stdin.
return map(int,stdin.read().split())
range = xrange # not for python 3.0+
mod=10**9+7
n,a,b,k=in_arr()
dp=[[0 for i in range(n+1)] for j in range(k+1)]
dp[0][a-1]=1
dp[0][a]=(-1)%mod
b-=1
for i in range(k):
temp=0
for j in range(n):
temp=(temp+dp[i][j])%mod
x=int(abs(b-j))
x-=1
if x<=0:
continue
dp[i+1][max(0,j-x)]=(dp[i+1][max(0,j-x)]+temp)%mod
dp[i+1][min(n,j+x+1)]=(dp[i+1][min(n,j+x+1)]-temp)%mod
dp[i+1][j]=(dp[i+1][j]-temp)%mod
dp[i+1][j+1]=(dp[i+1][j+1]+temp)%mod
ans=0
temp=0
for i in range(n):
temp+=dp[k][i]
temp%=mod
ans+=temp
ans%=mod
pr_num(ans)
```
| 90,498 |
Provide tags and a correct Python 2 solution for this coding contest problem.
Imagine that you are in a building that has exactly n floors. You can move between the floors in a lift. Let's number the floors from bottom to top with integers from 1 to n. Now you're on the floor number a. You are very bored, so you want to take the lift. Floor number b has a secret lab, the entry is forbidden. However, you already are in the mood and decide to make k consecutive trips in the lift.
Let us suppose that at the moment you are on the floor number x (initially, you were on floor a). For another trip between floors you choose some floor with number y (y ≠ x) and the lift travels to this floor. As you cannot visit floor b with the secret lab, you decided that the distance from the current floor x to the chosen y must be strictly less than the distance from the current floor x to floor b with the secret lab. Formally, it means that the following inequation must fulfill: |x - y| < |x - b|. After the lift successfully transports you to floor y, you write down number y in your notepad.
Your task is to find the number of distinct number sequences that you could have written in the notebook as the result of k trips in the lift. As the sought number of trips can be rather large, find the remainder after dividing the number by 1000000007 (109 + 7).
Input
The first line of the input contains four space-separated integers n, a, b, k (2 ≤ n ≤ 5000, 1 ≤ k ≤ 5000, 1 ≤ a, b ≤ n, a ≠ b).
Output
Print a single integer — the remainder after dividing the sought number of sequences by 1000000007 (109 + 7).
Examples
Input
5 2 4 1
Output
2
Input
5 2 4 2
Output
2
Input
5 3 4 1
Output
0
Note
Two sequences p1, p2, ..., pk and q1, q2, ..., qk are distinct, if there is such integer j (1 ≤ j ≤ k), that pj ≠ qj.
Notes to the samples:
1. In the first sample after the first trip you are either on floor 1, or on floor 3, because |1 - 2| < |2 - 4| and |3 - 2| < |2 - 4|.
2. In the second sample there are two possible sequences: (1, 2); (1, 3). You cannot choose floor 3 for the first trip because in this case no floor can be the floor for the second trip.
3. In the third sample there are no sought sequences, because you cannot choose the floor for the first trip.
Tags: combinatorics, dp
Correct Solution:
```
from sys import stdin, stdout
from collections import Counter, defaultdict
from itertools import permutations, combinations
raw_input = stdin.readline
pr = stdout.write
def in_num():
return int(raw_input())
def in_arr():
return map(int,raw_input().split())
def pr_num(n):
stdout.write(str(n)+'\n')
def pr_arr(arr):
pr(' '.join(map(str,arr))+'\n')
# fast read function for total integer input
def inp():
# this function returns whole input of
# space/line seperated integers
# Use Ctrl+D to flush stdin.
return map(int,stdin.read().split())
range = xrange # not for python 3.0+
mod=10**9+7
n,a,b,k=in_arr()
dp=[[0 for i in range(n+1)] for j in range(k+1)]
dp[0][a-1]=1
dp[0][a]=(-1)%mod
b-=1
for i in range(k):
temp=0
for j in range(n+1):
temp=(temp+dp[i][j])%mod
if i and int(abs(b-j))>1:
temp-=dp[i-1][j]
temp%=mod
dp[i][j]=temp
if j<n:
x=int(abs(b-j))
x-=1
if x<=0:
continue
dp[i+1][max(0,j-x)]=(dp[i+1][max(0,j-x)]+temp)%mod
dp[i+1][min(n,j+x+1)]=(dp[i+1][min(n,j+x+1)]-temp)%mod
#dp[i+1][j]=(dp[i+1][j]-1)%mod
#dp[i+1][j+1]=(dp[i+1][j+1]+1)%mod
if i and int(abs(b-j))>1:
temp+=dp[i-1][j]
temp%=mod
ans=0
temp=0
for i in range(n):
temp+=dp[k][i]
temp%=mod
if int(abs(i-b))>1:
temp-=dp[k-1][i]
temp%=mod
ans+=temp
ans%=mod
if int(abs(i-b))>1:
temp+=dp[k-1][i]
temp%=mod
pr_num(ans)
```
| 90,499 |
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