problem_id stringclasses 100
values | submission_id stringlengths 10 10 | status stringclasses 2
values | code stringlengths 6 806 |
|---|---|---|---|
p02572 | s470076102 | Accepted | def solve():
N = int(input())
A = list(map(int, input().split()))
square = []
for i in A:
square.append(i**2)
return (sum(A)**2 - sum(square))//2 % (10**9+7)
print(solve())
|
p02572 | s377307668 | Accepted | n = int(input())
a = list(map(int,input().split()))
s = sum(a)
t = sum(map(lambda x:x**2,a))
ans = ((s**2 - t)//2) % (10**9 + 7)
print(ans) |
p02572 | s455412220 | Accepted | n = int(input())
arr = [int(a) for a in input().split()]
summ = sum(arr)
ans = 0
for i in range(n-1):
a = arr[i]
summ -= arr[i]
b = summ
ans += (a*b)%(int(1e9+7))
print(ans%(int(1e9+7))) |
p02572 | s271682490 | Accepted | N = int(input())
A = list(map(int, input().split()))
mod = int(1e+9 + 7)
rui = 0
for i in range(N):
rui = (rui + A[i])%mod
answer = 0
for i in range(N-1):
rui = (rui - A[i])%mod
answer = (answer + rui * A[i])%mod
print(answer) |
p02572 | s828957500 | Accepted | n = int(input())
a = list(map(int, input().split()))
MOD = pow(10, 9) + 7
two_inv = pow(2, -1, MOD)
sq = []
for x in a:
sq.append(x ** 2 % MOD)
s = sum(a) % MOD
s_sq = sum(sq) % MOD
print((pow(s, 2, MOD) - s_sq) * two_inv % MOD) |
p02572 | s816077918 | Accepted | N=int(input())
A=list(map(int,input().split()))
A.reverse()
ans=0
tempsum=0
for i in range(len(A)-1):
tempsum+=A[i]
ans=ans+tempsum*A[i+1]
print(ans%(10**9+7)) |
p02572 | s905468325 | Accepted | n = int(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) |
p02572 | s839863123 | Accepted | N = int(input())
A = list(int(a) for a in input().split())
MOD = 10**9 + 7
S = sum(A)
ans = 0
for i in range(N-1):
S -= A[i]
ans += (A[i] * S) % MOD
print(ans%MOD) |
p02572 | s032644936 | Accepted | N = int(input())
A = list(map(int, input().split()))
sumA = sum(A)
ans = 0
for i in range(len(A)):
sumA -= A[i]
ans += sumA * A[i]
print(ans % 1000000007) |
p02572 | s423503023 | Accepted | n = int(input())
mod = 1000000007
a = [int(i)%mod for i in input().split()]
s = [0]*(n+1)
for i in range(n)[::-1]:
s[i] = (s[i+1] + a[i])%mod
ans = 0
for i in range(n-1):
ans += s[i+1]*a[i]%mod
ans %= mod
print(ans) |
p02572 | s590391592 | Accepted | n = int(input())
a = list(map(int, input().split()))
mod = 1000000007
total = 0
sum_sqr = 0
sqr_sum = 0
for i in range(n):
sum_sqr = (sum_sqr + a[i])
sum_sqr = (sum_sqr * sum_sqr)
for i in range(n):
sqr_sum = (sqr_sum + ((a[i] * a[i])))
# print(sqr_sum, sum_sqr)
total = (sum_sqr - sqr_sum) // 2
print(total%mod) |
p02572 | s825042889 | Accepted | p = 10**9+7
def pow(x,m):
if m==0:
return 1
if m==1:
return x
if m%2==0:
return (pow(x,m//2)**2)%p
else:
return (x*(pow(x,(m-1)//2)**2)%p)%p
N = int(input())
A = list(map(int,input().split()))
a1 = sum(A)%p
B = [A[i]**2 for i in range(N)]
a2 = 0
for i in range(N):
a2 = (a2+B[i])%p
ans = (((a1*a1)%p-a2)%p * pow(2,p-2))%p
print(ans) |
p02572 | s581557820 | Accepted | mod=10**9 + 7
n=int(input())
a=list(map(int,input().split()))
ans=0
total=sum(a)
for i in a:
total -= i
ans += total*i
print(ans%mod) |
p02572 | s609242981 | Accepted | #!/usr/bin/env python
n = int(input())
a = list(map(int, input().split()))
mod = int(1e9)+7
total = sum(a)
ans = 0
for i in range(n):
ans += (a[i]*(total-a[i]))%mod
total -= a[i]
print(ans%mod)
|
p02572 | s645247087 | Accepted | n = int(input())
a = list(map(int,input().split()))
inf = 10 ** 9 + 7
S = sum(a)
S2 = 0
for i in a:
S2 += i * i
print((S*S - S2)//2 % inf) |
p02572 | s710099591 | Accepted | import copy
N = int(input())
A = list(map(int,input().split()))
mod = 10**9+7
partial_sum = copy.deepcopy(A)
sum_now = A[N-1]
for j in range(N-2,-1,-1):
sum_now = int((sum_now+A[j])%mod)
partial_sum[j] = sum_now
res = 0
for i in range(N-1):
res = (res + (A[i]*partial_sum[i+1])%mod) %mod
print(int(res))
|
p02572 | s203576930 | Accepted | import sys
from itertools import accumulate
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10 ** 9)
INF = 1 << 60
MOD = 1000000007
def main():
N, *A = map(int, read().split())
csum = [0]
csum.extend(accumulate(A))
ans = 0
for i, a in enumerate(A):
ans = (ans + a * (csum[N] - csum[i + 1]) % MOD) % MOD
print(ans)
return
if __name__ == '__main__':
main()
|
p02572 | s427962021 | Accepted | MOD = 10**9 + 7
n = int(input())
a = list(map(int, input().split()))
rs = [0]
for i in range(n):
rs.append(rs[-1] + a[n - 1 - i])
ans = 0
for i in range(n - 1):
ans += a[i] * rs[n - 1 - i] % MOD
print(ans % MOD) |
p02572 | s521036204 | Accepted | n = int(input())
arr = list(map(int,input().split()))
result = 0
sum = arr[0]
for i in range(1,len(arr)):
result += (sum*arr[i])
sum+=arr[i]
print(result%1000000007)
|
p02572 | s805574914 | Accepted | import copy
n = int(input())
a = list(map(int,input().split()))
a_2 = copy.copy(a)
a_2.reverse()
sinu = [0] * n
t = 0
for i in range(n):
t += a_2[i]
sinu[i] += t
sinu.reverse()
ans = 0
for i in range(n-1):
#print(a[i],sinu[i+1])
ans += a[i] * sinu[i+1]
print(ans%(10**9+7))
|
p02572 | s383570176 | Accepted | mod = 10**9+7
def main():
n = int(input())
a = list(map(int, input().split()))
wa = sum(a)%mod
ans = 0
for i in range(n):
wa -= a[i]%mod
ans += (a[i]*wa)
ans %= mod
print(ans)
if __name__ == "__main__":
main() |
p02572 | s432754658 | Accepted | n=int(input())
a=list(map(int,input().split()))
mod=1000000007
sum=0
tmp=0
o=0
while(o<n):
tmp = (a[o]%mod + tmp%mod)%mod
o += 1
for i in range(n):
tmp=(tmp%mod-a[i]%mod)%mod
sum=((a[i]%mod)*tmp)%mod+sum%mod
print(sum%mod)
|
p02572 | s256000904 | Accepted | n = int(input())
a = list(map(int, input().split()))
s = 0
for i in range(n):
s = s + a[i]
e = s * s
ss = 0
for i in range(n):
ss += a[i] * a[i]
p = (e - ss) // 2
print(p % (10**9 + 7)) |
p02572 | s356118854 | Accepted | MOD = 10 ** 9 + 7
N = int(input())
A = list(map(int, input().split()))
s = sum(A)
ans = 0
for i in range(N - 1):
s -= A[i]
ans = (ans + A[i] * s) % MOD
print(ans) |
p02572 | s474586076 | Accepted | N = int(input())
l = list(map(int,input().split()))
mod = 10**9 + 7
area = sum(l) * sum(l)
for i in l:
area -= i*i
ans = area//2
ans = ans % mod
print(ans)
|
p02572 | s391772639 | Accepted | I=lambda:list(map(int,input().split()))
mod=10**9+7
n,=I()
l=I()
pre=l.copy()
suf=l.copy()
for i in range(n-2,-1,-1):
suf[i]+=suf[i+1]
ans=0
#print(suf)
for i in range(n-1):
ans+=(l[i]*suf[i+1])
ans%=mod
print(ans)
|
p02572 | s451204957 | Accepted | # -*- coding: utf-8 -*-
n = int(input())
a_list = list(map(int, input().split()))
s = 0
summation = 0
for i in a_list:
s += i
for i in a_list:
s -= i
summation += i * (s)
print(summation % (10 ** 9 + 7)) |
p02572 | s282895814 | Accepted | n = int(input())
li = list(map(int, input().split()))
res = 0
sum1 = sum(li)
sum2 = 0
m = 10**9 + 7
for i in range(0, len(li)-1):
sum2 += li[i]
res = (res + li[i]*(sum1-sum2))%m
print(res) |
p02572 | s818001040 | Accepted | n = int(input())
A = [*map(int, input().split())]
s = sum(A)
s *= s
for a in A: s -= a * a
s //= 2
print(s % (10**9 + 7))
|
p02572 | s194208749 | Accepted | n = int(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 += a[i]*s % mod
ans = ans % mod
print(ans % mod) |
p02572 | s772426242 | Accepted | n=int(input())
a=list(map(int,input().split()))
s=[0]*(n+1)
for i in range(n):
s[i+1] = s[i] + a[i]
MOD = 10**9+7
result = 0
for i in range(n):
result += a[i]*(s[n] - s[i+1])%MOD
print(result%MOD)
|
p02572 | s209176829 | Accepted | n = int(input())
a = [int(i) for i in input().split()]
s = [0 for i in range(n)]
s[-2] = a[n-1]
for i in range(3, n+1):
s[-i] = s[-(i-1)] + a[-(i-1)]
ans = 0
for i in range(n):
ans += a[i] * s[i]
print(ans % ((10**9)+7))
|
p02572 | s701259448 | Accepted | N=int(input())
A=list(map(int,input().split()))
mod=10**9+7
summy=[]
a=0
for i in range(N):
a += A[i]
a %= mod
summy.append(a)
ans=0
for i in range(N-1):
ans += summy[N-2-i]*A[N-1-i]
ans %= mod
print(ans) |
p02572 | s587782937 | Accepted | from itertools import accumulate
def main():
n = int(input())
a = list(map(int, input().split()))
mod = 10 ** 9 + 7
ac = list(accumulate(a))
ans = 0
for i in range(n):
ans += a[i] * (ac[-1] - ac[i])
ans %= mod
print(ans)
if __name__ == '__main__':
main()
|
p02572 | s234122198 | Accepted | def main():
input() # n
array = [int(x) for x in input().split()]
mod = 10 ** 9 + 7
total = 0
center_blocks = 0
for x in array:
total += x
center_blocks += x ** 2
total = total ** 2
return (total - center_blocks) // 2 % mod
if __name__ == '__main__':
print(main())
|
p02572 | s142991548 | Accepted | n = int(input())
*arr, = map(int, input().split())
modulo = 10 ** 9 + 7
p = arr.copy()
p.append(0)
for i in range(len(p) - 2, -1, -1):
p[i] = (p[i] + p[i + 1]) % modulo
ans = 0
for i in range(n):
ans += arr[i] * p[i + 1]
ans %= modulo
print(ans)
|
p02572 | s664050134 | Accepted | N = int(input())
A = list(map(int,input().split()))
a = 0
s = 0
for i in range(N):
a = (a+A[i])%(10**9+7)
for i in range(N-1):
a = a-A[i]
s = (s+A[i]*a)%(10**9+7)
print(s) |
p02572 | s103749549 | Accepted | N =int(input())
A = list(map(int,input().split()))
suma = sum(A)
Ans = 0
for a in A:
suma -= a
Ans += suma*a
Ans = Ans % (10**9+7)
print(Ans) |
p02572 | s157453944 | Accepted | n = int(input())
a = list(map(int, input().split()))
A = sum(a)
s = 0
for i in range(n-1):
A = A - a[i]
b = (a[i]*A)%(10**9+7)
s = s + b
print(s%(10**9+7)) |
p02572 | s119485925 | Accepted | N = int(input())
As = list(map(int, input().split()))
sum = 0
for i in range(N):
sum += As[i]
sum %= 10**9+7
ans = 0
for i in range(N):
sum -= As[i]
ans += As[i]*sum
ans %= 10**9+7
print(ans)
|
p02572 | s304804812 | Accepted | from sys import stdin, setrecursionlimit
from collections import Counter, deque, defaultdict
from math import floor, ceil
from bisect import bisect_left
from itertools import combinations, accumulate
setrecursionlimit(100000)
INF = int(1e10)
MOD = int(1e9 + 7)
def main():
from builtins import int, map
N = int(input())
A = list(map(int, input().split()))
cA = list(accumulate(A))
ans = 0
for i in range(N - 1):
term = A[i] * (cA[-1] - cA[i]) % MOD
ans = (ans + term) % MOD
print(ans)
if __name__ == '__main__':
main()
|
p02572 | s498730211 | Accepted | s = int(input())
a = list(map(int,input().split()))
mod = 10 ** 9 + 7
ans = 0
sum_a = sum(a)
for i in range(s):
sum_a -= a[i]
ans += sum_a * a[i]
print(ans%mod) |
p02572 | s863309710 | Accepted | import sys
def _i(): return int(sys.stdin.readline().strip())
def _ia(): return map(int, sys.stdin.readline().strip().split())
MOD = 10**9 + 7
def main():
n = _i()
a = list(_ia())
s = [0] * n
for i in range(n-2, -1, -1):
s[i] = s[i+1] + a[i+1]
ans = 0
for ai, si in zip(a, s):
ans = (ans + (ai * si)) % MOD
return ans
if __name__ == "__main__":
print(main())
|
p02572 | s242716201 | Accepted | N = int(input())
A = list(map(int,input().split()))
p = 0
c = len(A) - 1
total = 0
while 0 < c:
p += A[c]
total = total + p * A[c-1]
if total >= 1000000007:
total %= 1000000007
c -= 1
print(total)
|
p02572 | s414398747 | Accepted | n = int(input())
numbers = list(map(int, input().split()))
result = 0
sum_of_numbers = sum(numbers)
for i in range(n - 1):
sum_of_numbers -= numbers[i]
result += numbers[i] * sum_of_numbers
result %= 1000000007
print(result) |
p02572 | s001629953 | Accepted | n = int(input())
a = list(map(int, input().split()))
length = len(a)
total = sum(a)
ans = 0
for i in range(0,length):
total -= a[i]
ans += (a[i] * total)
print(ans % (10**9 + 7)) |
p02572 | s356626492 | Accepted | #import
#=input()
n=int(input())
#=map(int,input().split())
a=list(map(int,input().split()))
#=[list(map(int,input().split())) for _ in range()]
mod = 10 ** 9 + 7
sum = 0
for i in range(n):
sum += a[i]
s = 0
for i in range(n-1):
sum -= a[i]
s = (s + a[i] * sum) % mod
print(s) |
p02572 | s077477051 | Accepted | #!/usr/bin/env python3
import sys
input=sys.stdin.readline
mod=10**9+7
n=int(input())
arr=list(map(int,input().split()))
ans=0
sums=sum(arr)
for val in arr:
ans+=(val*sums)%mod
ans-=(val*val)%mod
print((ans*pow(2,mod-2,mod))%mod) |
p02572 | s679573903 | Accepted | MOD = 10**9 + 7
def solve(n, a):
t = sum(a)
return sum((t-x)*x for x in a) // 2 % MOD
n = int(input())
a = list(map(int, input().split()))
print(solve(n, a))
|
p02572 | s270476326 | Accepted | n=input()
a=input().split()
sum=0
for i in range(len(a)):
a[i]=(int)(a[i])
for i in a:
sum+=i
ans=0
ans+=(sum**2)
for i in a:
ans-=i*i
print((ans//2)%(10**9+7)) |
p02572 | s869606589 | Accepted | N = int(input())
A = list(map(int, input().split()))
from itertools import combinations
num = 10**9 + 7
ans = 0
B = []
b = 0
for i in reversed(A[1:]):
b += i
B.append(b)
B.reverse()
for x, y in zip(A[:-1], B):
ans += x*y
ans %= num
print(ans)
|
p02572 | s502720656 | Accepted | MOD = 10**9+7
N = int(input())
A = list(map(int,input().split()))
ruiseki = [A[i] for i in range(N)]
for i in range(1,N):
ruiseki[i]=ruiseki[i]+ruiseki[i-1]
ans = 0
for i in range(1,N):
ans =(ans + ((A[i]%MOD)*(ruiseki[i-1]%MOD))%MOD)%MOD
print(ans)
|
p02572 | s305987000 | Accepted | n=int(input())
a=list(map(int,input().split()))
mod=pow(10,9)+7
sa=[0]
tmp=0
for x in a:
tmp+=x
sa.append(tmp)
ans=0
for i in range(n-1):
ans+=a[i]*(sa[n]-sa[i+1])
ans%=mod
print(ans) |
p02572 | s527682912 | Accepted | def resolve():
n = int(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 | s977392713 | Accepted | N = int(input())
a = list(map(int,input().split()))
a_s = sum(a)
mod = 10**9+7
s = 0
for i in range(N-1):
b = a[i]
a_s -= b
s += b*(a_s)
s %= mod
print(s) |
p02572 | s042041463 | Accepted | n = int(input())
A = list(map(int,input().split()))
total = sum(A)
ans = 0
for i in range(n):
total -= A[i]
ans += A[i]*(total)
print(ans%(10**9 + 7)) |
p02572 | s789045542 | Accepted | import numpy as np
def main():
MOD = 10**9 + 7
N = int(input())
A = np.array(list(map(int, input().split())), dtype="i4")
A = A % MOD
rsumA = np.cumsum(A[::-1]) % MOD
count = 0
for i in range(len(A)-1):
a = A[i]
other = rsumA[len(A) - i - 2]
count += (a * other) % MOD
count %= MOD
print(count)
if __name__ == '__main__':
main()
|
p02572 | s599329791 | Accepted | N = int(input())
As = list(map(int, input().split()))
S = 0
T = 0
for i in range(N):
S += As[i]
T += (As[i] * As[i]) % 1000000007
# print(S)
# print(T)
A = S*S % 1000000007
B = T % 1000000007
X = (A - B) % 1000000007
print((X * int((1000000007 + 1)/2)) % 1000000007) |
p02572 | s807597507 | Accepted | # = map(int, input().split())
N = int(input())
A = list(map(int, input().split()))
mod = 10**9 + 7
S = sum(A)%mod
ans = 0
for k in range(N-1):
S -= A[k]
S %= mod
ans += S*A[k]
ans %= mod
print(ans) |
p02572 | s300019292 | Accepted | import sys
input = sys.stdin.readline
N = int(input())
A = list(map(int, input().split()))
mass = [0]*(N+1)
for i in range(N):
mass[i+1] = mass[i] + A[i]
answer = 0
for i in range(N-1):
answer += (A[i]*(mass[N]-mass[i+1]))
print(answer % (10**9 + 7)) |
p02572 | s766947330 | Accepted | N = int(input())
A = list(map(int, input().split()))
base = 10 ** 9 + 7
X = 0
Y = 0
for i in A:
X += i * i
Y += i
X %= base
Y %= base
Y = (Y * Y) % base
ans_ = ( Y - X ) % base
m = pow(2, base-2, base)
#print(m)
print( (ans_ * m) % base ) |
p02572 | s737363612 | Accepted | n=int(input())
alist=list(map(int,input().split()))
MOD=10**9+7
nijo=0
for i in range(n):
nijo+=(alist[i]**2)
gokei=sum(alist)
ans=(gokei**2-nijo)
ans=ans//2
ans=ans%MOD
print(ans) |
p02572 | s441022314 | Accepted | N = int(input())
A = list(map(int,input().split()))
total = sum(A)
ans = 0
for i in A:
total-=i
ans+=total*i
ans%=(10**9+7)
print(ans) |
p02572 | s998636643 | Accepted | n = int(input())
a = list(map(int, input().split()))
MOD = 10**9+7
acc = [0]
ans = 0
for i in a:
acc.append(acc[-1]+i)
acc = acc[1:]
for i, v in enumerate(a):
ans += (v*(acc[-1]-acc[i]))%MOD
print(ans%MOD) |
p02572 | s746712383 | Accepted | import numpy as np
N = int(input())
A = np.array([int(i) for i in input().split()])
sum = 0
#二乗和だけは1項ずつ求めてmodをとる
#for x in A:
# sum += x
# sum %= (10**9+7)
sum = A.sum() % (10**9+7)
sum2 = 0
for x in A:
sum2 += x*x
sum2 %= (10**9+7)
#sum2 = (A**2).sum() % (10**9+7)
ans = (sum**2 - sum2) % (10**9+7)
if ans < 0:
ans += (10**9+7)
ans *= int((10**9+7+1)/2)
ans %= (10**9+7)
print(int(ans))
|
p02572 | s706914114 | Accepted | n = int(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 | s663995793 | Accepted | import sys
input = sys.stdin.buffer.readline
from itertools import accumulate
MOD = 10**9 + 7
N = int(input())
A = [0] + list(map(int, input().split()))
C = list(accumulate(A))
ans = 0
for i in range(1, N):
ans += A[i] * (C[-1] - C[i])
ans %= MOD
print(ans)
|
p02572 | s989232248 | Accepted | N=int(input())
A=list(map(int,input().split()))
mod=10**9+7
inv_A=A[::-1]
b = [0]*N
b[0]=inv_A[0]
for i in range(1,N):
b[i] = (b[i-1]+inv_A[i])%mod
inv_b = b[::-1]
print( sum(A[i]*inv_b[i+1]%mod for i in range(0,N-1))%mod ) |
p02572 | s623156248 | Accepted | N = int(input())
A = list(map(int,input().split()))
MOD = 10**9+7
t = sum(A)**2
d = sum(a*a for a in A)
print(((t-d)//2)%MOD) |
p02572 | s797192279 | Accepted | n = int(input())
mod = 10**9+ 7
a = list(map(int,input().split()))
ans = (sum(a)%mod)**2 - sum([x**2%mod for x in a])
ans *= 5*10**8+4
ans %= mod
print(ans) |
p02572 | s432711457 | Accepted | n = int(input())
a = list(map(int,input().split()))
ans = 0
mod = 10**9+7
s = [0]*n
s[-1] = a[-1]
for i in range(n-2,-1,-1):
s[i] = (s[i+1]+a[i])%mod
for i in range(n-1):
ans = (ans + (a[i]*s[i+1]))%mod
print(ans) |
p02572 | s841193345 | Accepted | import sys
import itertools
sys.setrecursionlimit(1000000000)
from heapq import heapify,heappop,heappush,heappushpop
import math
import collections
import copy
import bisect
mod = 10**9 + 7
if __name__ == "__main__":
n = int(input())
a = list(map(int,input().split()))
a.sort()
prefix = [a[0]]
for i in range(1,n):
prefix.append(prefix[i-1] + a[i])
ans = 0
for i in range(n-1):
d = (a[i]*(prefix[-1] - prefix[i]))%mod
ans = ans + d
ans = ans%mod
print(ans) |
p02572 | s898360890 | Accepted | N = int(input())
A = list(map(int, input().split()))
mod = 10**9 + 7
s = sum(A)
key = 0
for i in range(N):
s -= A[i]
key += s*A[i]
print(key % mod) |
p02572 | s633069967 | Accepted | n = int(input())
a = list(map(int, input().split()))
mod = 10**9+7
ans = 0
aa=sum(a)
for i in range(n):
aa-=a[i]
ans += a[i]*aa
ans %= mod
print(ans)
|
p02572 | s577534870 | Accepted | N = int(input())
A = list(map(int,input().split()))
mod = 1000000000 + 7
S = sum(A)
S2 = sum(map(lambda x: x*x,A))
ans = (S*S - S2)// 2 % mod
print(ans) |
p02572 | s058682102 | Accepted | n = int(input())
an = [int(num) for num in input().split()]
an_total = sum(an)
answer = 0
for i in range(len(an)-1):
an_total -= an[i]
answer += an[i] * an_total
print(answer%1000000007) |
p02572 | s061111966 | Accepted | n = int(input())
L = [int(i) for i in input().split()]
sq = 0
for i in range(n):
sq += L[i]**2
tmp = (pow(sum(L),2) - sq) // 2
print(tmp % (pow(10,9)+7)) |
p02572 | s964202963 | Accepted | n=int(input())
a=list(map(int,input().split()))
s2=int(sum(a)*sum(a))
a2=[int(i*i) for i in a]
ans1=int((s2-sum(a2))//2)
print(int(ans1%(10**9+7))) |
p02572 | s344115141 | Accepted | n = int(input())
a = list(map(int, input().split()))
z = 0
for i in range(n):
z += a[i]
e = z % 2
y = (z ** 2) % 2000000014
x = 0
for j in range(n):
x += a[j] ** 2
x = x % 2000000014
w = int(((y - x) / 2) % 1000000007)
print(w) |
p02572 | s171042996 | Accepted | N = int(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 | s571265436 | Accepted | import sys
input = lambda : sys.stdin.readline().rstrip()
sys.setrecursionlimit(max(1000, 10**9))
write = lambda x: sys.stdout.write(x+"\n")
n = int(input())
a = list(map(int, input().split()))
s1 = 0
s2 = 0
M = 10**9+7
for item in a:
s1 += item
s2 += item**2
s1 %= M
s2 %= M
ans = (s1**2 - s2)*pow(2, M-2, M)
print(ans%M) |
p02572 | s470585628 | Accepted | n = int(input())
a = list(map(int, input().split()))
mod = 10**9+7
array_sum = sum(a) % mod
ans = 0
for i in range(n):
ans += a[i] * array_sum % mod
ans -= a[i] * a[i] % mod
print((ans * pow(2,-1,mod)) % mod) |
p02572 | s619164828 | Accepted | n = int(input())
A = list(map(int, input().split()))
mod = 10**9+7
s = 0
ans = 0
for a in A:
ans += s*a
ans %= mod
s += a
s %= mod
print(ans)
|
p02572 | s256821859 | Accepted | n = int(input())
A = list(map(int, input().split()))
S = sum(A)
S2 = sum(map(lambda x: x * x, A))
print((S*S-S2)//2 % 1000000007) |
p02572 | s224684303 | Accepted | n = int(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 | s510113236 | Accepted | import sys
import itertools
tokens = itertools.chain.from_iterable(map(str.split, sys.stdin))
mod = 1000000007
n = int(next(tokens))
a = [int(next(tokens)) % mod for _ in range(n)]
sms = []
sma = sum(a)
for i in range(n):
sma -= a[i]
sms.append(sma)
#print(sms)
m = 0
for i in range(n - 1):
sm = sms[i]
#print(i, a[i], sm)
m = (m + a[i] * sm) % mod
print(m)
|
p02572 | s076433640 | Accepted | n = int(input())
a = list(map(int, input().split(" ")))
res = 0
ruiseki = 0
for j in range(n):
if j == 0:
continue
ruiseki += a[j-1]
res = res + a[j]*ruiseki
print(res % ((10 **9)+7)) |
p02572 | s517983339 | Accepted | n = int(input())
a = list(map(int, input().split()))
x = 0
y = 0
for i in range(0,n):
x = x + a[i]
for i in range(0,n):
y = y + (a[i]**2)
print(((x**2-y)//2) % (10**9+7)) |
p02572 | s812864441 | Accepted | N = input()
nums = list(map(int, input().split()))
rests = []
rest_sum = 0
for i in reversed(nums):
rest_sum += i
rests.append(rest_sum)
sum_num = 0
for i in range(len(nums)-1):
sum_num += nums[i]*rests[-(i+2)]
if sum_num > 10**9 + 7:
sum_num = sum_num % (10**9 + 7)
print(sum_num) |
p02572 | s361336745 | Accepted | from collections import deque
def main():
import sys
input = sys.stdin.readline
MOD = 1000000007
n = int(input())
A = list(map(int, input().split()))
tmp = sum(A)
ans = 0
for i in range(n-1):
tmp -= A[i]
ans += A[i]*tmp
print(ans%MOD)
if __name__ == '__main__':
main()
|
p02572 | s840209102 | Accepted | n = int(input())
a_int = list(map(int, input().split()))
squ = 0
num = 10 ** 9 + 7
a_sum = 0
for i_sum in range(1, n):
a_sum += a_int[i_sum]
for i in range(0, n-1):
squ += a_int[i] * a_sum
a_sum -= a_int[i+1]
ans = squ % num
print(ans) |
p02572 | s979146422 | Accepted | MOD=10**9+7
N=int(input())
A=list(map(int,input().split()))
cum=[0]*(N+1)
for i in range(N):
cum[i+1]=(cum[i]+A[i])%MOD
ans=0
for i in range(N):
res=(cum[N]-cum[i+1]+MOD)%MOD*A[i]%MOD
ans=(ans+res)%MOD
print(ans) |
p02572 | s146731322 | Accepted | N = int(input())
A = list(map(int ,input().split()))
MOD = 10**9+7
sum = 0
for i in range (N):
sum += A[i]
ans = 0
for i in range(N):
sum -= A[i]
ans += (A[i] * sum) % MOD
ans = ans % MOD
print(ans) |
p02572 | s494047759 | Accepted | def LI():
return list(map(int, input().split()))
N = int(input())
A = LI()
total = sum(A)
ans = 0
mod = pow(10, 9)+7
for i in range(N-1):
total -= A[i]
ans = (ans+total*A[i]) % mod
print(ans)
|
p02572 | s352635344 | Accepted | import sys
import math
def Ii():return int(sys.stdin.readline().rstrip())
def Mi():return map(int,sys.stdin.readline().split())
def Li():return list(map(int,sys.stdin.readline().split()))
n = Ii()
a = Li()
sa = 0
ans = 0
mod = 10**9+7
for i in range(n-1):
sa += a[i]
ans += sa*a[i+1]
ans %= mod
print(ans) |
p02572 | s643971867 | Accepted | N=int(input())
l=list(map(int,input().split()))
ans=0
i=0
S=sum(l)
while i<len(l)-1:
S=S-l[i]
ans+=l[i]*S
i+=1
print(ans%1000000007) |
p02572 | s036383307 | Accepted |
if __name__ == "__main__":
MOD = 10 ** 9 + 7
N=int(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 | s131736057 | Accepted | n = int(input())
a = list(map(int, input().split()))
mod = 10**9 + 7
ans = 0
s = sum(a)
for i in a:
s -= i
ans = (ans + (i * s))
ans = ans % mod
print(ans) |
p02572 | s416316017 | Accepted | N = int(input())
A = list(map(int, input().split()))
mod = 10**9+7
sum = 0
sum_1 = 0
for i in range(N):
sum += A[i]%mod
sum = (sum**2)%mod
for j in range(N):
sum_1 += (A[j]**2)%mod
sum2=sum-sum_1
if sum2<0:
sum2+=mod
ans=(sum2*500000004)%mod
print(int(ans))
|
p02572 | s203014666 | Accepted | n = int(input())
a = list(map(int,input().split()))
p = 0
q = a[0]
for i in range(1,n):
p += q*a[i]
p %= 1000000007
q += a[i]
q %= 1000000007
print(p) |
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