input stringlengths 20 127k | target stringlengths 20 119k | problem_id stringlengths 6 6 |
|---|---|---|
n = int(eval(input()))
arr = list(map(int,input().split()))
ans = 0
for i in range(len(arr)):
for j in range(i+1,len(arr)):
ans += (arr[i]*arr[j])%(1000000007)
ans %= 1000000007
print(ans) | n = int(eval(input()))
arr = list(map(int,input().split()))
ans = 0
tmp = 0
for i in range(n-1):
tmp += arr[i]%1000000007
ans += tmp*arr[i+1] % 1000000007
print((ans%1000000007))
| p02572 |
N = int(eval(input()))
A_list = tuple(map(int, input().split(' ')))
# print(N)
# print(A_list)
ret = 0
now_sum = sum(A_list)
# print("スタート{}".format(now_sum))
for i in range(len(A_list)):
now_sum -= A_list[i]
multiple_base = A_list[i]
# print('now_sumから{0}を引いて{1}'.format(A_list[i], now_sum))
before_total = 0
for q in range(i + 1, len(A_list)):
before_total += A_list[q]
# print("before_totalは{0}, multiple_baseは{1}, 掛け算で{2}".format(multiple_base, before_total, multiple_base * before_total))
ret += multiple_base * before_total
print((ret % 1000000007))
| N = int(eval(input()))
A_list = tuple(map(int, input().split(' ')))
# print(N)
# print(A_list)
ret = 0
now_sum = sum(A_list)
# print("スタート{}".format(now_sum))
for i in range(len(A_list)):
now_sum -= A_list[i]
multiple_base = A_list[i]
# print('now_sumから{0}を引いて{1}'.format(A_list[i], now_sum))
before_total = 0
# print("before_totalは{0}, multiple_baseは{1}, 掛け算で{2}".format(multiple_base, before_total, multiple_base * before_total))
ret += multiple_base * now_sum
print((ret % 1000000007))
| p02572 |
N=int(eval(input()))
A=list(map(int,input().split()))
T=0
x=0
L=10**9+7
for i in range(0,N):
for j in range(i+1,N):
x=x+A[j]
y=A[i]*x
T+=y
x=0
ans=T%L
print(ans)
| N=int(eval(input()))
A=list(map(int,input().split()))
MOD=10**9+7 #先に書いておく
s=[0] #sのリスト(累積和)
for i in range(0,N): #累積和を作る
s.append(s[i]+A[i])
sum=0
for j in range(0,N): #合計をだす
sum+=A[j]*(s[N]-s[j+1])
ans=sum%MOD #10^9+7で割った余りが答え
print(ans) | p02572 |
import sys
from itertools import accumulate
n = int(sys.stdin.buffer.readline())
a = list(map(int, sys.stdin.buffer.readline().split()))
aa = list(accumulate(a))
MOD = 10**9+7
ans = 0
for i in range(n):
ans += a[i]*(aa[n-1] - aa[i]) % MOD
ans %= MOD
print(ans)
| import sys
from itertools import accumulate
n = int(sys.stdin.buffer.readline())
a = list(map(int, sys.stdin.buffer.readline().split()))
aa = list(accumulate(a))
MOD = 10**9+7
ans = 0
for i in range(n):
ans += a[i]*(aa[n-1] - aa[i]) % MOD
print((ans%MOD))
| p02572 |
import sys
from itertools import accumulate
n = int(sys.stdin.buffer.readline())
a = list(map(int, sys.stdin.buffer.readline().split()))
aa = list(accumulate(a))
MOD = 10**9+7
ans = 0
for i in range(n):
ans += a[i]*(aa[n-1] - aa[i]) % MOD
print((ans%MOD))
| import sys
from itertools import accumulate
n = int(sys.stdin.buffer.readline())
a = list(map(int, sys.stdin.buffer.readline().split()))
aa = list(accumulate(a))
MOD = 10**9+7
ans = 0
for i in range(n):
ans += a[i]*(aa[n-1] - aa[i])
print((ans%MOD))
| p02572 |
n = int(eval(input()))
a = list(map(int,input().split()))
mod = 10**9 + 7
s = [0]*n
for i in range(n):
s[i] = sum(a[i+1:]) % mod
# print(s)
ans = 0
for i in range(n-1):
ans += a[i]*s[i] % mod
print((ans % mod)) | n = int(eval(input()))
a = list(map(int,input().split()))
mod = 10**9 + 7
s = [0]*n
for i in reversed(list(range(1,n))):
s[i-1] = s[i] + a[i]
# print(s)
ans = 0
for i in range(n-1):
ans += a[i]*s[i] % mod
print((ans % mod)) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
mod = (10**9)+7
goukei = 0
for i in range(N-1):
Ai = A[i]
AJ = A[i+1:]
goukei += sum(AJ)*Ai
goukei = goukei%mod
print(goukei) | N = int(eval(input()))
A = list(map(int, input().split()))
def xgcd(a, b):
x0, y0, x1, y1 = 1, 0, 0, 1
while b != 0:
q, a, b = a // b, b, a % b
x0, x1 = x1, x0 - q * x1
y0, y1 = y1, y0 - q * y1
return a, x0, y0
def modinv(a, m):
g, x, y = xgcd(a, m)
if g != 1:
raise Exception('modular inverse does not exist')
else:
return x % m
mod = (10**9)+7
sumA = sum(A)%mod
sumSq = sum([(i*i)%mod for i in A])%mod
r = (((sumA*sumA)%mod)-sumSq) * modinv(2, mod)
print((r%mod)) | p02572 |
import itertools
N = int(eval(input()))
A = list(map(int, input().split()))
MOD = 1000000007
ans = 0
B = list(itertools.combinations(A,2))
for i in range(len(B)):
ans += (B[i][0] * B[i][1]) % MOD
ans %= MOD
print(ans) | MOD = 1000000007
N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
s = sum(A)
for a in A:
s -= a
ans += (a * s)
ans %= MOD
print(ans) | p02572 |
N = int(eval(input()))
A = list(map(int,input().split()))
k = 1000000007
ans = 0
for s in range(len(A)-1):
ans += A[s]*sum(A[s+1:])
if ans>1000000007:
print((ans%k))
else:
print(ans) | N = int(eval(input()))
A = list(map(int,input().split()))
k = 1000000007
sm = sum(A)
ans = 0
for s in range(len(A)-1):
#ans += A[s]*sum(A[s+1:])
sm -= A[s]
ans += A[s]*sm
if ans>1000000007:
print((ans%k))
else:
print(ans)
| p02572 |
N = int(eval(input()))
Alst = list(map(int, input().split()))
ans = 0
l = len(Alst)
for i in range(l):
ans = (ans + Alst[i]*sum(Alst[i+1:]))%(10**9 +7)
print(ans) | N = int(eval(input()))
Alst = list(map(int, input().split()))
l = len(Alst)
Blst = [0]*l
k = 0
ans = 0
for i in range(l-1, 0, -1):
k = (k + Alst[i])%(10**9 + 7)
Blst[i] = k
for j in range(l-1):
ans = (ans + Alst[j] * Blst[j+1])%(10**9 + 7)
print(ans) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10 ** 9 + 7
total = 0
for i in range(N - 1):
for j in range(i + 1, N):
total += (A[i]%mod) * (A[j]% mod) % mod
total %= mod
print(total)
| N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10 ** 9 + 7
sum_a=0
for i in A:
sum_a+=i
sum_a%=mod
total=0
for i in range(N - 1):
sum_a -= A[i]
total+=A[i]*(sum_a)
total%=mod
print(total)
| p02572 |
from itertools import combinations
n = int(eval(input()))
A = list(map(int, input().split()))
a = list(combinations(A, 2))
ans = 0
for i, j in a:
ans += ((i*j) % (10**9+7))
print((ans % (10**9+7))) | n = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
for i in A:
for j in A:
ans += (i*j) % (10**9+7)
mi = sum([x ** 2 for x in A])
ans -= mi
ans = ans % (10**9+7)
print((int(ans/2))) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
S = [0 for _ in range(N+1)]
mod = 1000000007
for i in range(N-1):
st = 0
for j in range(i+1):
st += A[j] * A[i+1]
S[i+1] = S[i] + st
print((int(S[N-1] % mod))) | N = int(eval(input()))
A = list(map(int, input().split()))
S = [0 for _ in range(N+1)]
T = [0 for _ in range(N+1)]
mod = 1000000007
for i in range(N-1):
st = 0
T[i+1] = T[i] + A[i]
S[i+1] = S[i] + A[i+1] * T[i+1]
print((int(S[N-1] % mod))) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
comb = len(a) * (len(a) - 1) / 2
comb = int(comb)
sum = 0
for i in range(comb):
#print(a)
for i in range(1, len(a)):
#print(a[i])
sum = sum + a[0] * a[i]
a = a[1:]
#print(a)
print((sum % (10**9 + 7))) | n = int(eval(input()))
a = list(map(int, input().split()))
su = sum(a)
sus = 0
for i in a:
su = su - i
sus = sus + i * su
print((sus % (10**9 + 7))) | p02572 |
from itertools import combinations
N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9 + 7
cnt = 0
for x,y in combinations(A,2):
z = x * y % mod
cnt += z
print((cnt % mod)) | N = int(eval(input()))
A = [0] + list(map(int, input().split()))
mod = 10**9 + 7
t = sum(A)
ans = 0
for i in range(1,N+1):
t -= A[i]
ans += A[i] * t % mod
print((ans % mod)) | p02572 |
N=int(eval(input()))
*A,=list(map(int,input().split()))
t=10**9+7
S=[a%t for a in A]
ans=0
for i in range(N):
ans+=S[i]*sum(S[i+1:])
print((ans%t)) | N=int(eval(input()))
*A,=list(map(int,input().split()))
t=10**9+7
S=[a%t for a in A]
g=sum(S)
ans=0
for i in range(N):
g-=S[i]
ans+=S[i]*g%t
print((ans%t)) | p02572 |
import sys
BIG = 10**9 + 7
def sumpp(n,a):
acc = 0
for i in range(n-1):
acc += a[i] * sum(a[i+1:])
return acc % BIG
input = sys.stdin.readline
if __name__ == "__main__":
n = int(eval(input()))
a = list(map(int,input().split()))
print((sumpp(n,a)))
| import sys
input = sys.stdin.readline
BIG = 10**9 + 7
def sumpp(n,a):
acc = 0
tmp = 0
sumv = sum(a)
for i in range(n):
tmp += a[i]
acc += a[i] * (sumv - tmp)
return acc % BIG
if __name__ == "__main__":
n = int(eval(input()))
a = list(map(int,input().split()))
print((sumpp(n,a)))
| p02572 |
N = int(eval(input()))
A = [ int(v) for v in input().split(" ") ]
total = 0
for i in range(N):
total += A[i] * sum(A[i+1:])
print((total % (10**9+7))) | N = int(eval(input()))
A = [ int(v) for v in input().split(" ") ]
sum_A = sum(A)
total = 0
for i in range(N):
sum_A -= A[i]
total += A[i] * sum_A
print((total % (10**9+7))) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
a = [i % (10**9 + 7) for i in a]
ans = 0
for i in range(n - 1):
ans += a[i]*(sum(a[i+1:])%(10**9 + 7))
ans %= 10**9 + 7
print(ans) | n = int(eval(input()))
a = list(map(int, input().split()))
a = [i % (10**9 + 7) for i in a]
val = sum(a[1:])
l = [val]
for i in range(1, n):
val -= a[i]
l.append(val)
ans = 0
for i in range(n - 1):
ans += a[i]*l[i]
ans %= 10**9 + 7
print(ans) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
a = [i % (10**9 + 7) for i in a]
val = sum(a[1:])
ans = 0
for i in range(n - 1):
ans += a[i]*val
ans %= 10**9 + 7
val -= a[i + 1]
print(ans) | n = int(eval(input()))
a = list(map(int, input().split()))
val = sum(a[1:])
ans = 0
for i in range(n - 1):
ans += a[i]*val
ans %= 10**9 + 7
val -= a[i + 1]
print(ans) | p02572 |
from sys import stdin, stdout
def gmi(): return list(map(int, stdin.readline().strip().split()))
def gms(): return list(map(str, stdin.readline().strip().split()))
def gari(): return list(map(int, stdin.readline().strip().split()))
def gars(): return list(map(int, stdin.readline().strip().split()))
def gs(): return stdin.readline().strip()
def gls(): return list(stdin.readline())
def gi(): return int(stdin.readline())
n = gi()
ar = gari()
c = 0
ans = 0
for i in ar[:-1]:
c += 1
for j in ar[c:]:
ans += i*j
print((ans%1000000007))
| from sys import stdin, stdout
def gmi(): return list(map(int, stdin.readline().strip().split()))
def gms(): return list(map(str, stdin.readline().strip().split()))
def gari(): return list(map(int, stdin.readline().strip().split()))
def gars(): return list(map(int, stdin.readline().strip().split()))
def gs(): return stdin.readline().strip()
def gls(): return list(stdin.readline())
def gi(): return int(stdin.readline())
n = gi()
ar = gari()
c = 0
ans = 0
s = sum(ar)
sub = 0
for i in ar[:-1]:
sub += ar[c]
ans += i*(s-sub)
c += 1
print((ans%1000000007))
| p02572 |
def main():
N = int(eval(input()))
A = list(map(int, input().split()))
mod_v = 10**9 + 7
ans = [0] * (N + 1)
for i in range(0, N - 1):
ai = A[0]
aj = A[i + 1]
ans[0] += ai * aj
for j in range(1, N - 1):
if A[j - 1] != 0:
ans[j] = (ans[j - 1] - A[j - 1] * A[j]) // A[j - 1] * A[j]
else:
for k in range(j, N - 1):
ai = A[k]
aj = A[k + 1]
ans[j] += ai * aj
ret = 0
for k in range(0, N):
ret += ans[k]
ret = ret % mod_v
print(ret)
if __name__ == '__main__':
main() | def calc(A, N, i):
ans = 0
ai = A[i]
for i in range(i, N - 1):
aj = A[i + 1]
ans += ai * aj
return (ans)
def main():
N = int(eval(input()))
A = list(map(int, input().split()))
mod_v = 10**9 + 7
ans = [0] * (N + 1)
for i in range(0, N - 1):
if A[i] != 0:
ans[i] = calc(A, N, i)
break
for j in range(i + 1, N - 1):
if A[j] != 0:
ans[j] = (ans[j - 1] - A[j - 1] * A[j]) // A[j - 1] * A[j]
else:
ans[j] = 0
ret = 0
for k in range(0, N):
ret += ans[k]
ret = ret % mod_v
print(ret)
if __name__ == '__main__':
main() | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
m = 10 ** 9 + 7
for i in range(N - 1):
ans += A[i] * sum(A[i + 1:])
ans %= m
print(ans) | N = int(eval(input()))
A = list(map(int, input().split()))
B = list(a ** 2 for a in A)
m = 10 ** 9 + 7
ans = int((sum(A) ** 2) // 2)
ans %= m
ans -= int(sum(B) // 2)
ans %= m
print(ans) | p02572 |
t = int(eval(input()))
s = [int(i) for i in input().split()]
c = 0
for i in range(1, t):
c += sum(s[:i]) * s[i]
mod = 10**9 + 7
print((c%mod)) | t = int(eval(input()))
s = [int(i) for i in input().split()]
c = 0
n = s[0]
for i in range(1, t):
c += n * s[i]
n += s[i]
mod = 10**9 + 7
print((c%mod)) | p02572 |
N = int(eval(input()))
A = list(map(int,input().split()))
c = 0
for i in range(N-1):
for j in range(i+1,N):
c += (A[i] * A[j]) %(10**9+7)
print((c%(10**9+7))) | N = int(eval(input()))
A = list(map(int,input().split()))
sumA = sum(A)
c = 0
for i in range(N-1):
c+= A[i]* (sumA-A[i])
sumA-= A[i]
print((c%(10**9+7))) | p02572 |
import itertools
N = int(eval(input()))
A_list = list(map(int, input().split()))
A_list.insert(0, 0)
product_dict = {}
for i, j in itertools.combinations(list(range(len(A_list))), 2):
product_dict[str(i) + "&" + str(j)] = A_list[i] * A_list[j]
sum = 0
for i in range(1, N):
for j in range(i + 1, N + 1):
sum += product_dict[str(i) + "&" + str(j)]
sum = sum % 1000000007
print(sum)
| N = int(eval(input()))
A_list = list(map(int, input().split()))
A_list.insert(0, 0)
cum_sum = 0
cum_sum_list = []
for i in range(N + 1):
cum_sum += A_list[i]
cum_sum_list.append(cum_sum)
ans = 0
for i in range(1, N+1):
ans += A_list[i] * (cum_sum_list[N] - cum_sum_list[i])
ans = ans % 1000000007
print(ans) | p02572 |
import itertools
N = int(eval(input()))
A = list(map(int, input().split()))
sm=0
mod=10**9+7
for i in itertools.combinations(A,2):
sm+=(i[0]*i[1])%mod
sm%=mod
print(sm) | N = int(eval(input()))
A = list(map(int, input().split()))
sm=0
mod=10**9+7
s=sum(A)
for i in A:
s-=i
sm+=i*s
sm%=mod
print(sm) | p02572 |
_ = eval(input())
nums = [int(x) for x in input().split(" ")]
res = 0
sums = [sum(nums[i:]) for i in range(1, len(nums))]
for i, ni in enumerate(nums[:-1]):
res += ni*sums[i]
res %= 10**9 + 7
print(res) | _ = eval(input())
nums = [int(x) for x in input().split(" ")]
res = 0
sums = []
for n in nums[1:][::-1]:
if sums:
sums.append(sums[-1]+n)
else:
sums.append(n)
sums.reverse()
#print(sums)
for i, ni in enumerate(nums[:-1]):
res += ni*sums[i]
res %= 10**9 + 7
print(res) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
sum = 0
A.sort(reverse=False)
for i in range(N):
for j in range(N-(i+1)):
sum += A[i]*A[j+i+1]
print((sum%((10**9)+7))) |
n = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9+7
s = sum(A)
ans = 0
for i in range(n):
s -= A[i]
ans += (A[i] * s) % mod
print((ans%mod)) | p02572 |
import itertools
N = int(eval(input()))
A = list(map(int,input().split()))
#Aa=[]
#for i in A:
#Aa.append(i%(10**9+7))
#print(Aa)
ans = 0
for i,j in itertools.combinations(A,2):
#print(i,j)
ans += i*j
#print(ans)
print((ans%(10**9+7))) | N = int(eval(input()))
A = list(map(int,input().split()))
MOD = 10**9+7
S = sum(A)
ans = 0
for i in range(N-1):
S -= A[i]
ans = (ans + S*A[i])%MOD
print(ans) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
s = 0
t = sum(a)
m = 10 ** 9 + 7
for i in range(n - 1):
s += a[i] * (t - sum(a[0:i + 1])) % m
print((s % m)) | n = int(eval(input()))
a = list(map(int, input().split()))
s = sum(a)
t = 0
m = 10 ** 9 + 7
for i in range(n - 1):
s -= a[i]
t += a[i] * s % m
print((t % m)) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
mod = pow(10, 9) + 7
b = [0] * (n + 1)
for i in range(n):
b[i + 1] = a[i] + b[i]
ans = 0
for i in range(n - 1):
ans += (b[n] - b[i + 1]) * a[i]
ans %= mod
print(ans) | n = int(eval(input()))
a = list(map(int, input().split()))
s = sum(a)
ans = 0
mod = pow(10, 9) + 7
for i in a:
s -= i
ans = (ans + s * i) % mod
print(ans) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
s = sum(a)
ans = 0
mod = pow(10, 9) + 7
for i in a:
s -= i
ans = (ans + s * i) % mod
print(ans) | n = int(eval(input()))
a = list(map(int, input().split()))
mod = pow(10, 9) + 7
s = sum(a) % mod
ans = s * s % mod
for i in a:
ans -= i * i
ans %= mod
ans = ans * pow(2, mod - 2, mod) % mod
print(ans) | p02572 |
n = int(eval(input()))
a_list = list(map(int, input().split()))
ans = 0
m = 10 ** 9 + 7
for i in range(n):
for j in range(i + 1, n):
ans += a_list[i] * a_list[j]
ans %= m
print(ans)
| n = int(eval(input()))
a_list = list(map(int, input().split()))
sum_a = sum(a_list)
ans = 0
m = 10 ** 9 + 7
for i in range(n):
sum_a -= a_list[i]
ans += a_list[i] * sum_a
ans %= m
print(ans)
| p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
sum_of_product = 0
for i in range(N - 1):
for j in range(i + 1, N):
sum_of_product += A[i] * A[j]
if sum_of_product >= 10 ** 9 + 7:
sum_of_product %= 10 ** 9 + 7
print(sum_of_product) | eval(input())
A = list(map(int, input().split()))
sum_list = sum(A)
sum_of_product = 0
for i in A:
sum_list -= i
sum_of_product = ((sum_list * i) % (10 ** 9 + 7) + sum_of_product) % (10 ** 9 + 7)
print(sum_of_product) | p02572 |
from itertools import combinations
n = int(eval(input()))
a = list(map(int, input().split()))
comb = combinations(a, 2)
res = 0
for i, j in comb:
res += i*j
print((res%(10**9+7))) | n = int(eval(input()))
lst = list(map(int, input().split()))
ans = 0
summ = sum(lst)
summ_sq = summ**2
for i in range(n):
ans += lst[i]**2
res = (summ_sq-ans)//2
print((res % ((10**9)+7))) | p02572 |
import math
class BitIndexedTree:
'''NOTES: 1-origin-indexed
'''
def __init__(self, itemCount):
self.itemCount = itemCount
self.items = [0 for i in range(itemCount+1)]
def add(self, i,value):
while i <= self.itemCount:
self.items[i] += value
i += (i & (-i))
def sumFromStart(self, end):
summary = 0
i = end
while i > 0:
summary += self.items[i]
i -= (i & (-i))
return summary
def sum(self, start,end):
summary = self.sumFromStart(end) - self.sumFromStart(start-1)
return summary
if __name__ == "__main__":
MOD = 10 ** 9 + 7
N=int(eval(input()))
A=list(map(int,input().split()))
BIT=BitIndexedTree(N)
for n in range(N):
BIT.add(n+1, A[n])
ans = 0
for n in range(N-1):
# print(A[n],BIT.sum(n+2,N),A[n] * BIT.sum(n+2,N))
# print(MOD)
ans += ((A[n] * BIT.sum(n+2,N)) % MOD)
print((ans % MOD))
|
if __name__ == "__main__":
MOD = 10 ** 9 + 7
N=int(eval(input()))
A=list(map(int,input().split()))
Asum = sum(A) % MOD
ans = 0
for n in range(N-1):
Asum -= A[n]
ans += ((A[n] * Asum) % MOD)
print((ans % MOD))
| p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
mod = 10**9+7
ans = 0
for i in range(n-1):
for j in range(i+1, n):
ans += a[i] * a[j] % mod
print((ans % mod)) | n = int(eval(input()))
a = list(map(int, input().split()))
mod = 10**9+7
ans = 0
sum_j = [0] * n
sum_tmp = 0
for i in reversed(list(range(n))):
sum_tmp += a[i]
sum_j[i] = sum_tmp
for i in range(n-1):
ans += a[i] * sum_j[i+1] % mod
print((ans % mod))
| p02572 |
# from itertools import combinations
n=int(eval(input()))
a=[int(i) for i in input().split()]
pro=0
for i in range(n-1):
for j in range(i+1,n):
pro+=a[i]*a[j]
print((pro%(10**9+7))) | # from itertools import combinations
def Sum(A, n):
array_sum = 0
for i in range(0, n, 1):
array_sum = array_sum + A[i]
array_sum_square = array_sum * array_sum
individual_square_sum = 0
for i in range(0, n, 1):
individual_square_sum += A[i] * A[i]
return (array_sum_square -individual_square_sum) // 2
n=int(eval(input()))
a=[int(i) for i in input().split()]
print((Sum(a,n)%(10**9+7)))
| p02572 |
n = int(eval(input()))
a_list = list(map(int, input().split()))
s = 0
for i in range(n-1):
for j in range(i+1, n):
s += a_list[i] * a_list[j]
ans = s % 1000000007
print(ans)
| n = int(eval(input()))
a_list = list(map(int, input().split()))
sum_l = sum(a_list)
ans = 0
for i in range(n-1):
sum_l -= a_list[i]
ans += sum_l * a_list[i]
print((ans % 1000000007)) | p02572 |
num=int(eval(input()))
date=list(map(int,input().split(" ")))
sum=0
for i in range(num):
for j in range(num-i-1):
sum+=date[i]*date[i+j+1]
print((sum%(10**9+7))) | num=int(eval(input()))
date=list(map(int,input().split(" ")))
sum0=0
sum1=0
for i in range(num):
sum0+=date[i]
for i in range(num):
sum0-=date[i]
sum1+=date[i]*sum0
print((sum1%(10**9+7))) | p02572 |
N = int(eval(input()))
As = list(map(int, input().split()))
Asum = sum(As)
ans = 0
for index, A in enumerate(As):
Asum = sum(As)
ans += (A * (Asum - A))
ans = ans % (10**9+7)
# print(As)
As = As[1:]
# print(As)
print(ans) | N = int(eval(input()))
As = list(map(int, input().split()))
Asum = sum(As)
ans = 0
for index, A in enumerate(As):
ans += (A * (Asum - A))
ans = ans % (10**9+7)
Asum -= A
# print(
# print(As)
print(ans) | p02572 |
mod = 10 ** 9 + 7
N = int(eval(input()))
A = list([int(x) % mod for x in input().split(" ")])
print((sum((A[i] * A[j]) % mod for i in range(0,N-1) for j in range(i+1,N)) % mod)) | mod = 1000000007
N = int(eval(input()))
A = list([int(x) % mod for x in input().split(" ")])
"""
累積話を計算しておく: O(N)
"""
_sum = 0
for i in range(N):
_sum += A[i]
_sum %= mod
"""
1重ループ内で下記を行う: O(N)
- 端のブロックを累積和から崩す（減算）
- 端のブロックと累積和をかける
- modをとる
"""
ans = 0
for i in range(N):
# 累積和の端のブロックを崩す
_sum -= A[i]
ans += A[i] * _sum
ans %= mod
print(ans)
| p02572 |
m = 10**9 + 7
n = eval(input())
a = list(map(int,input().split()))
ans = 0
for i in range (len(a)):
for j in range (i+1,len(a)):
ans += a[i]*a[j]
ans = ans%m
print(ans) | m = 10**9 + 7
n = eval(input())
a = list(map(int,input().split()))
ans = 0
s = sum(a)
for i in a:
s -= i
ans += s*i
ans = ans%m
print(ans) | p02572 |
import itertools
N = int(eval(input()))
A = list(map(int, input().split()))
r = 0
m = 10**9+7
for x in itertools.combinations(A, 2):
r += x[0]*x[1]
print((r % m)) | import itertools
N = int(eval(input()))
A = list(map(int, input().split()))
sa = sum(A)
r = 0
xx = sa
m = 10**9+7
for x in A:
xx -= x
r += x*xx
r = r % m
print(r) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
bs = 10**9 + 7
sm = 0
for i, ai in enumerate(a):
sm += (ai * sum(a[(i+1):])) % bs
sm = sm % bs
print(sm) | n = int(eval(input()))
a = list(map(int, input().split()))
bs = 10**9 + 7
s = sum(a)
sm = 0
for i, ai in enumerate(a):
s -= ai
sm += (ai * s) % bs
sm = sm % bs
print(sm) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
A_sum = sum(A)
ans = 0
for i in range(N-1):
B = A.pop(0)
A_sum -= B
ans += A_sum*B
print((ans % (10**9+7)))
| N = int(eval(input()))
A = list(map(int, input().split()))
A_sum = sum(A)
ans = 0
for i in range(N-1):
A_sum -= A[i]
ans += A_sum*(A[i])
print((ans%(10**9+7))) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
MOD = 10 ** 9 + 7
a = [num % MOD if num >= MOD else num for num in a]
ans = 0
for i in range(len(a)):
for j in range(i + 1, len(a)):
acc = a[i] * a[j]
ans += acc % MOD if acc >= MOD else acc
ans %= MOD
print(ans) | n = int(eval(input()))
a = list(map(int, input().split()))
MOD = 10 ** 9 + 7
a = [num % MOD if num >= MOD else num for num in a]
sum_list = [0]
for i in range(n):
sum_list.append((a[i] + sum_list[i]) % MOD)
# print(sum_list)
ans = 0
for i in range(len(a)):
ans += a[i] * (sum_list[-1] - sum_list[i + 1])
ans %= MOD
print(ans) | p02572 |
import itertools
n = int(eval(input()))
a = list(map(int, input().split()))
MOD = 10**9+7
ans = 0
for i in range(n-1):
ans = (ans+(a[i]*sum(a[i+1:])%MOD))%MOD
print(ans) | n = int(eval(input()))
a = list(map(int, input().split()))
t = sum(a)
MOD = 10**9+7
ans = 0
for i in range(n-1):
t -= a[i]
ans = (ans+(a[i]*t%MOD))%MOD
print(ans) | p02572 |
def main():
N = int(eval(input()))
A = [int(n) for n in input().split()]
M = 10 ** 9 + 7
combinations = [(i, j) for i in range(N-1) for j in range(i+1, N)]
print((sum([A[i] * A[j] for (i, j) in combinations]) % M))
main()
| def main():
N = int(eval(input()))
A = [int(n) for n in input().split()]
M = 10 ** 9 + 7
ans = 0
for i in range(N-1):
ans += A[i] * sum([A[j] for j in range(i+1, N)]) % M
print((ans % M))
main()
| p02572 |
def main():
N = int(eval(input()))
A = [int(n) for n in input().split()]
M = 10 ** 9 + 7
ans = 0
for i in range(N-1):
ans += A[i] * sum([A[j] for j in range(i+1, N)]) % M
print((ans % M))
main()
| def main():
N = int(eval(input()))
A = [int(n) for n in input().split()]
M = 10 ** 9 + 7
ans = 0
cache = sum(A) % M
for i in range(N-1):
cache -= A[i]
ans += A[i] * cache % M
print((ans % M))
main()
| p02572 |
# -*- coding: utf-8 -*-
def main():
N = int(eval(input()))
A = [int(i) for i in input().split()]
#ax = itertools.combinations(A, 2)
ans = 0
for i in range(N):
for j in range(i+1,N):
ans = (ans + A[i]*A[j]) % 1000000007
#print(A[i],A[j],ans)
print(ans)
if __name__ == "__main__":
main()
| # -*- coding: utf-8 -*-
def main():
N = int(eval(input()))
A = [int(i) for i in input().split()]
#N = 100000
#A = [i for i in range(1,100000)]
sum_a = sum(A)% 1000000007
ans = 0
for i in range(N):
sum_a = (sum_a - A[i])% 1000000007
ans = (ans + sum_a*A[i] ) % 1000000007
#print((sum_a-A[i])*A[i]/2 ,ans)
print(ans)
if __name__ == "__main__":
main()
| p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
inf = 10**9+7
aa = [0]*N
for i in range(N):
aa[i] = A[i]**2
X = sum(A)**2 - sum(aa)
print(((X//2)%inf)) | N = int(eval(input()))
A = list(map(int, input().split()))
sa = sum(A)
INF = 10**9+7
ans = 0
for i in range(N):
sa -= A[i]
ans += (A[i]*sa)%INF
print((ans%INF)) | p02572 |
import itertools
def main():
n = int(eval(input()))
# d,t,s = map(int, input().split())
a = list(map(int, input().split()))
# s = input()
l = []
for i in range(len(a)):
l.append(i)
c_list = list(itertools.combinations(l, 2))
sm = 0
for tpl in c_list:
sm += (a[tpl[0]] * a[tpl[1]]) % (10**9+7)
print((sm % (10**9+7)))
if __name__ == '__main__':
main()
| def main():
n = int(eval(input()))
# d,t,s = map(int, input().split())
a = list(map(int, input().split()))
# s = input()
sm = 0
for i in range(len(a)):
for j in range(i+1,len(a)):
sm += (a[i]% (10**9+7) * a[j% (10**9+7)]) % (10**9+7)
print((sm% (10**9+7)))
if __name__ == '__main__':
main()
| p02572 |
def main():
n = int(eval(input()))
# d,t,s = map(int, input().split())
a = list(map(int, input().split()))
# s = input()
sm = 0
for i in range(len(a)):
for j in range(i+1,len(a)):
sm += (a[i]% (10**9+7) * a[j% (10**9+7)]) % (10**9+7)
print((sm% (10**9+7)))
if __name__ == '__main__':
main()
| def main():
n = int(eval(input()))
# d,t,s = map(int, input().split())
a = list(map(int, input().split()))
# s = input()
mod = 10**9+7
s = sum(a)
sm = 0
for i in a:
s -= i
sm += i * s % mod
print((sm % mod))
if __name__ == '__main__':
main()
| p02572 |
N = int(eval(input()))
nums = list(map(int,input().split()))
calcs = []
for i in range(N):
a = nums[i]
for j in range(i+1, N):
calcs.append(a * nums[j])
print((sum(calcs) % (1000000000+7))) | N = int(eval(input()))
nums = list(map(int,input().split()))
total = 0
for i in range(N):
a = nums[i]
b = sum(nums[i+1:])
total += a*b
print((total % (1000000000+7))) | p02572 |
N = int(eval(input()))
nums = list(map(int,input().split()))
def calc():
total = 0
for i in range(N):
a = nums[i]
b = sum(nums[i+1:])
total += a*b
return total
print((calc() % (1000000000+7)))
| N = int(eval(input()))
nums = list(map(int,input().split()))
total = 0
sums = []
tmp = 0
for i in range(1, N):
tmp += nums[N-i]
sums.append(tmp)
for i in range(N-1):
a = nums[i]
b = sums[N-(i+2)]
total += a*sums[N-(i+2)]
print((total % (1000000000+7)))
| p02572 |
# from pprint import pprint
# import math
# import collections
n = int(eval(input()))
# n, k = map(int, input().split(' '))
a = list(map(int, input().split(' ')))
MOD = 10 ** 9 + 7
sum = 0
for i in range(n - 1):
for j in range(i + 1, n):
_ = a[i] * a[j]
sum += _
# print(i, j, _)
print((sum % MOD))
| # from pprint import pprint
# import math
# import collections
n = int(eval(input()))
# n, k = map(int, input().split(' '))
a = list(map(int, input().split(' ')))
MOD = 10 ** 9 + 7
wa = 0
for i in range(1, n):
wa += a[i]
# print('wa', wa)
ans = 0
j = 1
for i in range(n - 1):
ttl = a[i] * wa
ans += ttl
wa -= a[j]
j += 1
# print('new wa', wa)
print((ans % MOD))
| p02572 |
N= int(eval(input()))
ls= list(map(int,input().split()))
mod=10**9+7
ans=0
for i in range (N-1):
for j in range(i+1,N):
ans+=ls[i]*ls[j]%mod
ans%=mod
print(ans) | # AtCoder Beginner Contest 177
# C - Sum of product of pairs
N= int(eval(input()))
ls= list(map(int,input().split()))
mod=10**9+7
ans=0
accumls=[0]
for i in range (N):
accumls.append(accumls[-1]+ls[i])
for i in range (N-1):
ans+= ls[i]*(accumls[-1]-accumls[i+1])
ans%=mod
print(ans)
| p02572 |
# ------------------- fast io --------------------
import os
import sys
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")
# ------------------- fast io --------------------
from math import gcd, ceil
def pre(s):
n = len(s)
pi = [0] * n
for i in range(1, n):
j = pi[i - 1]
while j and s[i] != s[j]:
j = pi[j - 1]
if s[i] == s[j]:
j += 1
pi[i] = j
return pi
def prod(a):
ans = 1
for each in a:
ans = (ans * each)
return ans
def lcm(a, b): return a * b // gcd(a, b)
def binary(x, length=16):
y = bin(x)[2:]
return y if len(y) >= length else "0" * (length - len(y)) + y
N = int(eval(input()))
A = list(map(int, input().split()))
MOD = int(1e9) + 7
ans = 0
for i in range(N):
for j in range(i + 1, N):
ans += A[i] * A[j]
ans %= MOD
print(ans)
| # ------------------- fast io --------------------
import os
import sys
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")
# ------------------- fast io --------------------
from math import gcd, ceil
def pre(s):
n = len(s)
pi = [0] * n
for i in range(1, n):
j = pi[i - 1]
while j and s[i] != s[j]:
j = pi[j - 1]
if s[i] == s[j]:
j += 1
pi[i] = j
return pi
def prod(a):
ans = 1
for each in a:
ans = (ans * each)
return ans
def lcm(a, b): return a * b // gcd(a, b)
def binary(x, length=16):
y = bin(x)[2:]
return y if len(y) >= length else "0" * (length - len(y)) + y
N = int(eval(input()))
A = list(map(int, input().split()))
MOD = int(1e9) + 7
ans = 0
acc = 0
for i in A:
ans += i * acc
acc += i
ans %= MOD
acc %= MOD
print(ans)
| p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9 + 7
ans = 0
for i in range(N - 1):
ans += (A[i] * sum(A[(i + 1):]))
print((ans % mod))
| N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9 + 7
ans = 0
total = sum(A)
for i in range(N - 1):
total -= A[i]
ans += (A[i] * total)
print((ans % mod))
| p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
a = [A for A in a if a != 0]
from itertools import combinations
MOD = 10**9 + 7
ans = 0
for i,j in combinations(a, 2):
ans = ans + (i*j)%MOD
print((ans%MOD)) | n = int(eval(input()))
a = list(map(int, input().split()))
from itertools import accumulate
cumsum = list(accumulate(a[::-1]))[::-1]
MOD = 10**9+7
ans = 0
for i,A in enumerate(a[:-1]):
ans += A * cumsum[i+1]
ans = ans % MOD
print(ans) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
from itertools import accumulate
cumsum = list(accumulate(a[::-1]))[::-1]
MOD = 10**9+7
ans = 0
for i,A in enumerate(a[:-1]):
ans += A * cumsum[i+1]
ans = ans % MOD
print(ans) | n = int(eval(input()))
x = list(map(int, input().split()))
edge = sum(x)
print(((edge**2 - sum([X*X for X in x]))//2 % (10**9+7))) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
s = 0
for i in range(n):
for j in range(i + 1, n):
s += a[i] * a[j]
print((s % (10 ** 9 + 7)))
| n = int(eval(input()))
a = list(map(int, input().split()))
a_sum = 0
s = []
ans = 0
for i in range(n):
a_sum += a[i]
s.append(a_sum)
for i, j in enumerate(a):
ans += j * (s[n - 1] - s[i])
print((ans % (10 ** 9 + 7)))
| p02572 |
mod = 10**9 + 7
N = int(eval(input()))
array = [int(i) for i in input().split()]
output = 0
for i in range(N):
for j in range(i+1, N):
output += (array[i]%mod) * (array[j]%mod)
print((output%mod)) | mod = 10**9 + 7
N = int(eval(input()))
array = [int(i) for i in input().split()]
array_2 = [0]
for a in array:
array_2.append(array_2[-1]+a)
output = 0
for i in range(len(array)-1):
output += array[i] * (array_2[-1] - array_2[i+1])
print((output%mod)) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
_sum = 0
for i in range(N):
for j in range(i+1, N):
_sum += A[i] * A[j]
print((_sum % (10**9 + 7))) | N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9 + 7
ak = 0
ak_2 = 0
for i in range(N):
ak += A[i]
ak_2 += A[i] ** 2
s = int(((ak ** 2) - ak_2) // 2)
print((s % mod)) | p02572 |
import itertools
import collections
import math
import sys
sys.setrecursionlimit(2000000)
n = int(eval(input()))
a = list(map(int, input().split()))
mod = 10**9 + 7
ans = 0
data = [i for i in range(n)]
for i, j in itertools.combinations(data, 2):
ans += (a[i] % mod)*(a[j] % mod) % mod
ans %= mod
print(ans)
| n = int(eval(input()))
a = list(map(int, input().split()))
mod = 10**9 + 7
ans = 0
total = sum(a)
for i in range(n):
total -= a[i]
ans += a[i]*total
ans %= mod
print(ans)
| p02572 |
### ----------------
### ここから
### ----------------
import sys
from io import StringIO
import unittest
import itertools
def yn(b):
print(("Yes" if b==1 else "No"))
return
def resolve():
readline=sys.stdin.readline
#n,m,k=map(int, readline().rstrip().split())
mod=10**9+7
n=int(readline())
arr=list(map(int, readline().rstrip().split()))
ans=0
for p in itertools.combinations(arr,2):
ans=(ans+p[0]*p[1])%mod
#ss=readline().rstrip()
#yn(1)
print(ans)
return
if 'doTest' not in globals():
resolve()
sys.exit()
### ----------------
### ここまで
### ---------------- | ### ----------------
### ここから
### ----------------
import sys
from io import StringIO
import unittest
import copy
def yn(b):
print(("Yes" if b==1 else "No"))
return
def resolve():
readline=sys.stdin.readline
#n,m,k=map(int, readline().rstrip().split())
mod=10**9+7
n=int(readline())
arr=list(map(int, readline().rstrip().split()))
arr2=copy.copy(arr)
for i in range(1,n):
arr2[i]=(arr2[i]+arr2[i-1])%mod
base=arr2[n-1]+mod
ans=0
for i in range(n-1):
ans=(ans+arr[i]*((base-arr2[i])%mod))%mod
print(ans)
return
if 'doTest' not in globals():
resolve()
sys.exit()
### ----------------
### ここまで
### ---------------- | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
mod = 10**9+7
s = 0
for i in range(n-1):
for j in range(i+1, n):
s += (a[i]%mod*a[j]%mod)%mod
s %= mod
print(s)
| n = int(eval(input()))
a = list(map(int, input().split()))
mod = 10**9+7
s = 0
l = [0 for i in range(n)]
l[0] = a[0]
for i in range(1, n):
l[i] += l[i-1]
l[i]%=mod
l[i] += a[i]
l[i]%=mod
# print(l)
for i in range(1, n):
s+=((a[i]%mod)*(l[i-1]%mod))%mod
s%=mod
print(s)
| p02572 |
N = int(eval(input()))
As = list(map(int,input().split()))
sums = 0
moder = 1000000007
for i in range(N-1):
for j in range(N-i-1):
sums+=(As[i]*As[i+j+1])%moder
print((sums%moder)) | N = int(eval(input()))
As = list(map(int,input().split()))
sums = 0
moder = 1000000007
s=[0 for i in range(N-1)]
s[-1] = As[-1]
for i in range(N-2):
s[-(i+2)] = s[-(i+1)]+As[-(i+2)]
for i in range(N-1):
sums+= (As[i]*s[i])%moder
print((sums%moder)) | p02572 |
N = int(eval(input()))
A = list(map(int,input().split()))
P = 0
A_l = [num% (10**9+7) for num in A]
for i in range(N):
sum=0
for j in range(i+1,N):
sum += A_l[j]
P += A_l[i]*sum
ans = P%(10**9+7)
print(ans) | N = int(eval(input()))
A = list(map(int,input().split()))
P = 0
S = sum(A)
m = 10**9+7
for i in range(N):
S -= A[i]
P += A[i]*S
ans = P%m
print(ans) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
s = sum(A)
ans = 0
for i in range(N):
s = sum(A[i:N])
s -= A[i]
ans += A[i]*s
print((ans%((10**9)+7))) | N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
s = sum(A)
for i in range(N-1):
s -= A[i]
ans += A[i]*s
print((ans%((10**9)+7))) | p02572 |
n=int(eval(input()))
a=list(map(int,input().split()))
ans=0
for i in range(n):
ans+=a[i]*sum(a)
s=0
for i in range(n):
s+=a[i]*a[i]
ans=(ans-s)//2
ans=ans%(10**9+7)
print(ans)
| n=int(eval(input()))
a=list(map(int,input().split()))
ans=0
t=sum(a)
s=0
for i in range(n):
s+=a[i]*a[i]
ans=(t*t-s)//2
ans=ans%(10**9+7)
print(ans) | p02572 |
D = 10 ** 9 + 7
N = int(eval(input()))
L= list(map(int, input().split()))
ans = L[0] * L[1] % D
for n in range(2,N):
for l in range(n):
ans += L[n] * L[l] % D
print((ans % D))
| D = 10 ** 9 + 7
N = int(eval(input()))
L= list(map(int, input().split()))
ans = L[0] * L[1] % D
sub = L[0] + L[1]
for n in range(2,N):
ans += L[n] * sub
sub += L[n]
print((ans % D)) | p02572 |
N=int(eval(input()))
Alist=list(map(int,input().split()))
sum=0
for i in range(N-1):
for j in range((i+1),N):
sum=(sum+(Alist[i]*Alist[j]))%(10**9+7)
print(sum) | N=int(eval(input()))
Alist=list(map(int,input().split()))
sum1=0
sum2=0
for i in range(N):
sum1=sum1+Alist[i]
sum2=sum2+(Alist[i])**2
ans=(sum1**2-sum2)//2
print((ans%(10**9+7))) | p02572 |
n=eval(input())
m=0
MOD = 10 ** 9 + 7
from itertools import combinations
b=combinations
a=b(list(map(int,input().split())),2)
for i,j in a:
k=i*j
m+=k%MOD
m%=MOD
print(m) | N=int(eval(input()))
A=list(map(int, input().split()))
MOD = 10 ** 9 + 7
cumsum = [A[0]]
for i in range(1, N):
cumsum.append(A[i] + cumsum[i - 1])
ans = 0
for i in range(N):
ans += (A[i] * (cumsum[-1] - cumsum[i])) % MOD
ans %= MOD
print(ans) | p02572 |
n = int(eval(input()))
a = list(map(int, input().split()))
result= 0
for j in range(0,n):
result += a[j]*sum(a[j+1:n])
print((result%(10**9+7))) | n = int(eval(input()))
a = list(map(int, input().split()))
result= 0
asum = sum(a)
for j in range(0,n):
asum -= a[j]
result += a[j]*(asum)
print((result%(10**9+7)))
| p02572 |
a=int(eval(input()))
b = list(map(int, input().split()))
b.sort()
S=0
for i in range(0,a):
S=S+b[i]*sum(b[i+1:a])
print((S % (10**9+7))) | a=int(eval(input()))
b = list(map(int, input().split()))
b.sort()
S=0
c=sum(b)
for i in range(0,a):
c=c-b[i]
S=S+b[i]*c
print((S % (10**9+7))) | p02572 |
n = int(eval(input()))
list1 = list(map(int, input().split()))
s = 0
for i in range(n):
p = list1[i] * sum(list1[i+1:n])
s += p
print((s % (10**9 + 7))) | n = int(eval(input()))
list1 = list(map(int, input().split()))
s = 0
ss = sum(list1)
for i in range(n):
a = list1[i]
ss = ss - a
p = a * ss
s += p
print((s % (10**9 + 7))) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
mod = 10**9+7
B = list([x%mod for x in A])
for i in range(N-1):
for j in range(N):
if i < j:
ans = ans%mod + (B[i]%mod)*(B[j]%mod)
print((ans%mod)) | N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
hoge = 0
mod = 10**9+7
for i in range(N):
hoge = hoge + A[i]
hoge = hoge % mod
for i in range(N):
hoge = hoge - A[i]
if hoge < 0:
hoge = hoge + mod
ans = ans + A[i] * hoge
ans = ans % mod
print((ans%mod))
| p02572 |
from sys import stdin
import itertools
def main():
input = stdin.readline
N = int(eval(input()))
A = list(map(int,input().split()))
mod = (10 ** 9) +7
ans = 0
for i,j in itertools.combinations(list(range(N)),2):
ans = (ans + (A[i] * A[j])) % mod
print(ans)
if __name__ == "__main__":
main() | from sys import stdin
import itertools
def main():
input = stdin.readline
N = int(eval(input()))
A = list(map(int,input().split()))
mod = (10 ** 9) +7
ans = 0
total = sum(A)
for i in range(N):
total = total - A[i]
ans = (ans + (A[i] * total)) % mod
print(ans)
if __name__ == "__main__":
main() | p02572 |
import itertools
_ = eval(input())
A = list(map(int, input().split()))
mod = 10**9 + 7
print((sum([(ai * aj) % mod for ai, aj in itertools.combinations(A, 2)]) % mod))
| _ = eval(input())
A = list(map(int, input().split()))
mod = 10**9 + 7
s = 0
a = 0
for _a in A:
s += _a * a
a = (a + _a) % mod
print((s % mod))
| p02572 |
from itertools import *
N = int(eval(input()))
A = list(map(int,input().split()))
ans = 0
a = combinations(list(range(N)),2)
for i in a:
ans += A[i[0]] * A[i[1]]
print((ans % (10 ** 9 + 7))) | N = int(eval(input()))
A = list(map(int,input().split()))
s = [0]
for i in range(N):
s.append(s[i] + A[i])
ans = 0
for i in range(N):
ans += A[i] * (s[N] - s[i + 1])
print((ans % (10 ** 9 + 7)))
| p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9+7
ans = 0
for i in range(N-1):
ans += A[i] * sum(A[i+1:]) % mod
ans = ans%mod
print(ans) |
from itertools import accumulate
N = int(eval(input()))
A = list(map(int, input().split()))
B = list(accumulate(A))
mod = 10**9+7
ans = 0
sumA = sum(A)
for i in range(N-1):
ans += A[i] * (sumA-B[i]) % mod
ans = ans%mod
print(ans)
| p02572 |
def resolve():
import itertools
n = int(eval(input()))
A = list(map(int, input().split()))
B = itertools.combinations(A, 2)
ans = 0
for b in B:
ans += b[0] * b[1]
print((ans % (10**9 + 7)))
resolve() | def resolve():
n = int(eval(input()))
A = list(map(int, input().split()))
sm = sum(A) % (10**9 + 7)
ans = 0
for a in A:
sm -= a
ans += sm * a
ans %= (10**9 + 7)
print(ans)
resolve() | p02572 |
import itertools
def main():
N = int(eval(input()))
A = [int(a) for a in input().split(" ")]
p = 1000000007
ans = 0
for c in itertools.combinations(A, 2):
ans += (c[0] * c[1]) % p
ans = ans % p
print(ans)
main() | def main():
N = int(eval(input()))
A = [int(a) for a in input().split(" ")]
p = 1000000007
S = 0
Asq = 0
for i in range(len(A)):
x = A[i]
S += x % (2 * p)
Asq += (x * x) % (2 * p)
t = ((S * S) % (2 * p) - Asq) % (2 * p)
print((int(t / 2)))
main() | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
mod = 10**9+7
P = 0
Q = 0
for i in range(N-1):
for j in range(i+1, N):
P = A[i] % mod
Q = A[j] % mod
ans += (P * Q) % mod
print((ans % mod))
| N = int(eval(input()))
A = list(map(int, input().split()))
mod = 10**9+7
k = int((10**9 + 8)/2)
sum = 0
sum_1 = 0
for i in range(N):
sum += A[i]
sum = (sum**2)%mod
for j in range(N):
sum_1 += A[j]**2
sum_1 = (sum_1)%mod
ans = sum - sum_1
ans = (ans*k)%mod
print(ans)
| p02572 |
def sumPair(A):
L = len(A)
M = 1000000007
total_sum = 0
for i in range(0, L):
for j in range(i+1, L):
pair_m = A[i] * A[j]
total_sum = (total_sum + pair_m) % M
return total_sum
N = int(eval(input()))
A = list(map(int, input().rstrip().split()))
print((sumPair(A))) | def fastSumPair(A):
L = len(A)
M = 1000000007
# (a + b + c)**2 = a**2 + b**2 + c**2 + 2*(a*b + b*c + c*a)
# derive from this equation
# first array
A_1_sum = 0
for i in range(0, L):
A_1_sum = (A_1_sum + A[i])
A_1_sum = (A_1_sum ** 2)
# second array
A_2_sum = 0
for i in range(0, L):
A_2_sum = (A_2_sum + A[i] ** 2)
return int((A_1_sum - A_2_sum) // 2) % M
N = int(eval(input()))
A = list(map(int, input().rstrip().split()))
print((fastSumPair(A))) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
for i in range(N-1):
for j in range(i+1,N,1):
ans += A[i]*A[j]
print((ans%(10**9+7))) | N = int(eval(input()))
A = list(map(int, input().split()))
tmp = sum(A[1:])
ans = 0
for i in range(N-1):
ans += A[i]*tmp
tmp -=A[i+1]
print((ans%(10**9+7))) | p02572 |
d = 10 ** 9 + 7
n = int(eval(input()))
lista = [int(x) for x in input().split()]
for k in lista:
k %= d
total = 0
for i in range(n-1):
for j in range(i+1, n):
total += lista[i] * lista[j]
total %= d
print(total)
| d = 10 ** 9 + 7
n = int(eval(input()))
lista = [int(x) for x in input().split()]
for k in lista:
k %= d
totalJ = sum(lista)
total = 0
for i in range(n-1):
totalJ -= lista[i]
total += totalJ * lista[i]
total %= d
print(total)
| p02572 |
MOD = 10 ** 9 + 7
n = int(eval(input()))
alst = list(map(int, input().split()))
total = sum(alst)
ans = 0
for a in alst:
ans += a * (total - a)
ans %= MOD
ans *= pow(2, MOD - 2, MOD)
ans %= MOD
print(ans) | n = int(eval(input()))
alst = list(map(int, input().split()))
ans = (sum(alst) ** 2 - sum([a ** 2 for a in alst])) // 2
MOD = 10 ** 9 + 7
print((ans % MOD))
| p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
ans = 0
for i in range(len(A)):
for j in range(i + 1, len(A)):
ans = (ans + (A[i] * A[j]) % 1000000007) % 1000000007
print(ans) | N = int(eval(input()))
A = list(map(int, input().split()))
sum_a = sum(A)
ans = 0
for i in range(len(A)):
sum_a -= A[i]
ans = (ans + (A[i] * sum_a) % 1000000007) % 1000000007
print(ans) | p02572 |
n = int(eval(input()))
seq = list(map(int, input().split()))
a = 10 ** 9 + 7
res = 0
i = 0
j = 1
for i in range(n - 1):
b = 0
for j in range(i + 1, n):
b += seq[j]
res += (seq[i] * b) % a
print((res % a)) | n = int(eval(input()))
seq = list(map(int, input().split()))
a = 10 ** 9 + 7
s = sum(seq)
res = 0
for i in range(n - 1):
s -= seq[i]
res += (seq[i] * s) % a
print((res % a)) | p02572 |
N = int(eval(input()))
A = [int(e) for e in input().split()]
sum = 0
asum = 0
for i in A :
asum = asum + i*i
for j in A:
sum = sum + i*j
sum = ((sum - asum)/2)%1000000007
print((int(sum))) | N = int(eval(input()))
A = [int(e) for e in input().split()]
S = [0]
sum =0
for i in range(0, N):
S.append(S[i] + A[i])
for i in range(N):
sum = sum + (S[i+1]-A[i]) * A[i]
print((sum%1000000007)) | p02572 |
N=int(eval(input()))
A=list(map(int,input().split()))
for i in range(N):
A[i]=A[i]%(10**9+7)
ans=0
for i in range(N-1):
for j in range(i+1,N):
ans=(ans+A[i]*A[j])%(10**9+7)
print(ans)
| N=int(eval(input()))
A=list(map(int,input().split()))
wa=[0]*(N-1)
wa[0]=A[-1]
for i in range(1,N-1):
wa[i]=wa[i-1]+A[N-i-1]
ans=0
wa.reverse()
for i in range(0,N-1):
ans=(ans+wa[i]*A[i])%(10**9+7)
print(ans)
| p02572 |
N = int(eval(input()))
A = list(map(int,input().split()))
SUM = 0
for i in range(1,N):
for j in range(i):
SUM += A[i]*A[j]
print((SUM % (10**9+7))) | N = int(eval(input()))
A = list(map(int,input().split()))
sumA = sum(A)
SUM = 0
for i in range(1,N):
sumA -= A[i]
SUM += A[i]*sumA
print((SUM % (10**9+7))) | p02572 |
n=int(eval(input()))
a=list(map(int,input().split()))
sm=0
for i in range(n-1):
for j in range(i+1,n):
b=a[i]*a[j]
sm+=b
sm=sm%((10**9)+7)
print(sm)
| n=int(eval(input()))
a=list(map(int,input().split()))
sm=0
sumj=sum(a)
for i in range(n-1):
sumj-=a[i]
sm+=sumj*a[i]
print((sm%((10**9)+7)))
| p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
t = 0
for i in range(len(A) - 1):
for j in range(i + 1, len(A)):
t = (t + (A[i] * A[j])) % 1000000007
print(t) | N = int(eval(input()))
A = list(map(int, input().split()))
t = 0
S = sum(A)
c = 0
for i in range(len(A) - 1):
S -= A[i]
t = (t + (A[i] * S)) % 1000000007
print(t) | p02572 |
N = int(eval(input()))
A = list(map(int, input().split()))
t = 0
S = sum(A)
c = 0
for i in range(len(A) - 1):
S -= A[i]
t = (t + (A[i] * S)) % 1000000007
print(t) | N = int(eval(input()))
A = list(map(int, input().split()))
t = 0
S = sum(A)
c = 0
for i in range(len(A) - 1):
S -= A[i]
t = (t + (A[i] * S))
print((t % 1000000007)) | p02572 |
from itertools import combinations
N = int(eval(input()))
A = [int(i) for i in input().split(maxsplit=N)]
sumA = 0
for a, b in combinations(A, 2):
sumA += (a * b) % (10**9 + 7)
print((sumA % (10**9 + 7)))
| def resolve():
N = int(eval(input()))
A = [int(i) for i in input().split(maxsplit=N)]
presum = [0 for _ in range(N + 1)]
for i in range(N):
presum[i + 1] = presum[i] + A[i]
sumA = 0
for i in range(1, N):
sumA += (A[i] * (presum[i])) % (10**9 + 7)
print((sumA % (10**9 + 7)))
resolve()
| p02572 |
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