problem_id stringclasses 100 values | submission_id stringlengths 10 10 | status stringclasses 2 values | code stringlengths 6 806 |
|---|---|---|---|
p02572 | s989329031 | Accepted | n = int(input())
a = list(map(int, input().split()))
ans = sum(a) ** 2
for i in a:
ans -= i ** 2
print((ans // 2) % (10 ** 9 + 7)) |
p02572 | s055000196 | Accepted | n=int(input())
i = list(map(int, input().split()))
m=sum(i)
ans=0
for k in range(n):
ans+=(i[k]*(m-i[k]))
ans=ans//2
ans=ans%(10**9+7)
print(ans) |
p02572 | s489319997 | Accepted | N = int(input())
A_List = [int(i) for i in input().split()]
Y = 0
M = 10**9+7
tempSum = sum(A_List)
for x in A_List:
tempSum -= x
Y += x * tempSum
Y = Y%M
print(Y) |
p02572 | s376917121 | Accepted | #!/usr/bin/env python3
def solve(N, A):
MOD = 10**9 + 7
total = sum(A)
ans = 0
for i in range(N - 1):
total -= A[i]
ans += A[i] * total
ans %= MOD
return ans
def main():
N = int(input())
A = list(map(int, input().split()))
ans = solve(N, A)
print(ans)
if __name__ == "__main__":
main()
|
p02572 | s695649706 | Accepted | #coding: utf-8
MOD = 1000000000 + 7
N = int(input())
A = [int(x) for x in input().split()]
s = sum(A)
ret = 0
for a in A:
s -= a
ret += a * s
ret %= MOD
print(ret)
|
p02572 | s684827594 | Accepted | n = int(input())
A = map(int,input().split())
mod = 1000000007
ans = 0
tmp1, tmp2 = 0, 0
for m in A:
tmp1 = (tmp1+m) %mod
tmp2 = (tmp2+m*m%mod)%mod
ans = ((tmp1*tmp1)%mod-tmp2)%mod
if ans%2 ==0:
ans = ans/2
else:
ans =(ans+mod)/2
print(int(ans)) |
p02572 | s375811952 | Accepted | #dt = {} for i in x: dt[i] = dt.get(i,0)+1
import sys;input = sys.stdin.readline
inp,ip = lambda :int(input()),lambda :[int(w) for w in input().split()]
M = 10**9+7
n = inp()
x = ip()
sm = sum(x)
sq = sm*sm
ans = 0
for i in x: ans += i*i
ans = (sq-ans)//2
print(ans%M) |
p02572 | s796817812 | Accepted | N = int(input())
A = list(map(int,input().split()))
K = sum(A)
S = 0
for i in range(N-1):
K = K - A[i]
S = S + A[i]*K
ans = S%(10**9+7)
print(ans) |
p02572 | s299449138 | Accepted | n = input()
a = [int(num) for num in input().split(" ")]
mod_value = 10**9 + 7
sum = 0
total = 0
for i in reversed(range(1, len(a))):
sum += a[i]
total += a[i-1] * sum
print(total%mod_value)
|
p02572 | s943322288 | Accepted | import functools
import operator
N = int(input())
A = list(map(int, input().split()))
mod = 10**9+7
ans = 0
v = sum(A)
for i in range(N-1):
v -= A[i]
ans += A[i]*v
print(ans%mod)
|
p02572 | s899818420 | Accepted | n=int(input())
a=list(map(int, input().split()))
ans=0
s=sum(a)
for i in range(1,len(a)+1):
ans += a[i-1] * (s-a[i-1])
s = s-a[i-1]
ans = ans % (10 ** 9 + 7)
print(ans) |
p02572 | s845249933 | Accepted | MOD = 10**9+7
N = int(input())
A = list(map(int, input().split()))
A_sum = sum(A)
r = 0
for i, a in enumerate(A):
x = A[i]*(A_sum - a)
r = (r+x) % MOD
# print(r)
r = (r * pow(2, MOD-2, MOD)) % MOD
print(r) |
p02572 | s404135225 | Accepted | n=int(input())
A=list(map(int,input().split(" ")))
base=10**9+7
s=0
for i in range(1,len(A),1):
s=(s+A[i])%base
ans=0
for i in range(len(A)-1):
ans=(ans+(A[i]*s))%base
s=(s-A[i+1]+base)%base
print(ans)
|
p02572 | s847728211 | Accepted | n = int(input())
a = list(map(int, input().split()))
mod = 10 ** 9 + 7
ans = (sum(a) % mod) ** 2
for i in range(n):
ans -= a[i] ** 2
ans %= mod
if ans % 2 == 0:
print(ans // 2)
else:
print((ans + mod) // 2) |
p02572 | s035439702 | Accepted | N = int(input())
al = list(map(int,input().split()))
sss=0
pss=0
for i in range(1,N):
pss+=al[i-1]
sss+=al[i]*pss
print(sss%1000000007) |
p02572 | s884020738 | Accepted | N = int(input())
A = list(map(int,input().split()))
sum = 0
ans = 0
for i in range(1, N):
sum +=A[i-1]
sum = sum % (10**9 + 7)
ans = ans + (sum * A[i]) % (10**9 + 7)
ans = ans % (10**9 + 7)
print(ans) |
p02572 | s961218802 | Accepted | N = int(input())
A = [int(s) for s in input().split()]
MOD = 10**9 + 7
sums = [A[0]]
for a in A[1:]:
sums.append((a + sums[-1]) % MOD )
alls = 0
for i in range(1, len(A)):
# print(A[i], sums[i-1])
alls += A[i] * sums[i-1]
alls %= MOD
print(alls) |
p02572 | s144697232 | Accepted | N = int(input())
list_a = [int(x) for x in input().split(' ')]
# sum_a = sum(list_a) % (10**9+7)
# sum_a2 = sum([(x**2) % (10**9+7) for x in list_a])
sum_a = sum(list_a)
sum_a2 = sum([x**2 for x in list_a])
print(((sum_a ** 2 - sum_a2) // 2) % (10**9+7))
|
p02572 | s209853368 | Accepted | N=int(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))%(10**9+7)
print(ans%(10**9+7))
|
p02572 | s284327254 | Accepted | from sys import stdin
from itertools import accumulate
input = stdin.readline
n = int(input())
a = list(map(int,input().split()))
p = [0] + list(accumulate(a))
res = 0
for i in range(n-1,-1,-1):
res += (a[i] * p[i])%(10**9 + 7)
print(res % (10**9 + 7)) |
p02572 | s167214246 | Accepted | n = int(input())
A = [*map(int, input().split())]
MOD = 10**9 + 7
ans = b = 0
for a in A:
ans += a * b
ans %= MOD
b += a
print(ans)
|
p02572 | s611194712 | Accepted | N=int(input())
A=list(map(int,input().split()))
_sum=sum(A[1:])
mod=10**9+7
re=0
for i in range(0,N-1):
re+=A[i]*_sum
_sum-=A[i+1]
re%=mod
_sum%=mod
print(re%mod)
|
p02572 | s244892649 | Accepted | N=int(input())
A=list(map(int, input().split()))
MOD=10**9+7
tmp1 = 0
tmp2 = 0
for a in A:
tmp1 += a
tmp2 += (a**2)
ans = (tmp1**2 - tmp2)//2
print(ans%MOD) |
p02572 | s067574206 | Accepted | N = int(input())
A = list(map(int, input().split()))
c=0
d=sum(A)
for i in range(0,N-1):
d-=A[i]
c+=A[i]*d
if(c>10**9+7):
c%=(10**9+7)
print(c)
|
p02572 | s231778312 | Accepted | n = int(input())
A = list(map(int, input().split()))
M = 10**9 + 7
S = sum(A)
S2 = sum(map(lambda x: x**2, A))
print(((S**2 - S2)// 2)%M)
|
p02572 | s316987366 | Accepted | import sys
MOD = 10**9 + 7
N = int(input())
As = list(map(int, input().split()))
sumA = 0
for A in As:
sumA += A
sumA %= MOD
#print('# sumA:', sumA, file=sys.stderr)
ans = sumA * sumA % MOD
for A in As:
ans -= A * A % MOD
ans %= MOD
#print('# ans:', ans, file=sys.stderr)
inv2 = pow(2, MOD-2, MOD)
ans *= inv2
ans %= MOD
print(ans)
|
p02572 | s846352643 | Accepted | m=10**9+7
n=int(input())
a=[int(i) for i in input().split()]
ans=0 ; s=a[-1]
for i in range(n-2,-1,-1):
ans=(ans+s*a[i])%m
s=(s+a[i])%m
print(ans%m)
|
p02572 | s958295366 | Accepted | N = int(input())
A = [int(i) for i in input().split()]
B = [0]*N
res = 0
B[N-1] = A[N-1]
for i in range(1, N):
B[N-i-1] = B[N-i] + A[N-i-1]
for i in range(N-1):
res = (res + A[i] * B[i+1]) % (10**9+7)
print(res) |
p02572 | s541186415 | Accepted | def main():
n = int(input())
h = list(map(int,input().split()))
sum_h = sum(h)%(10**9 + 7)
ans = 0
for i in h:
i = i%(10**9 + 7)
sum_h -= i
ans += i*sum_h
print(ans%(10**9 + 7))
if __name__ == '__main__':
main() |
p02572 | s390523711 | Accepted | from itertools import accumulate
def main():
n=int(input())
a=list(map(int,input().split()))
aa=list(accumulate(a))
mod=10**9+7
ans=0
for i in range(n):
ans += a[i]*(aa[-1]-aa[i])%mod
print(ans%mod)
if __name__ == "__main__":
main() |
p02572 | s607879299 | Accepted | #!/usr/bin/env python3
import functools
M = 10 ** 9 + 7
def sum_mod(xs):
return functools.reduce(lambda x, y: (x + y) % M, xs) % M
def compute(bs):
term1 = sum_mod(bs) * sum_mod(bs) % M
term2 = sum_mod(b * b for b in bs)
double_res = (term1 - term2) % M
inv2 = pow(2, M - 2, M)
res = double_res * inv2 % M
return res
def main():
n = int(input())
bs = [int(b) for b in input().split()]
res = compute(bs)
print(res)
if __name__ == '__main__':
main() |
p02572 | s732449162 | Accepted | N = int(input())
A = list(map(int,input().split()))
ans = 0
num = sum(A)
for i in range(N - 1):
num -= A[i]
ans += A[i] * num
print(ans % (10 ** 9 + 7)) |
p02572 | s963825517 | Accepted | N = int(input()); MOD = pow(10,9)+7
A = list(map(int,input().split()))
S = sum(A)**2%MOD
nijo = 0
for x in A:
nijo = (nijo + x**2)%MOD
ans = (S-nijo)*pow(2,MOD-2,MOD)%MOD
print(ans%MOD) |
p02572 | s121768931 | Accepted | n=int(input())
a=list(map(int, input().split()))
s=sum(a)
ans=0
for i in range(n):
ans+=a[i]*(s-a[i])
print(ans//2%(10**9+7)) |
p02572 | s142610413 | Accepted | import math
n = int(input())
aL = list(map(int, input().split(" ")))
MOD = 10**9 + 7
aL2 = [aL[-1]]
for a in reversed(aL[:-1]):
aL2.append((aL2[-1] + a) % MOD)
aL2 = list(reversed(aL2))
ans = 0
for i in range(n - 1):
ans += aL[i] * aL2[i + 1]
ans %= MOD
print(ans) |
p02572 | s288196264 | Accepted | # 初期入力
import sys
input = sys.stdin.readline #文字列では使わない
N = int(input())
A = list(map(int, input().split()))
mod =10**9 +7
sum_a =sum(A)
ans =0
for i in range(N-1):
sum_a -=A[i]
ans +=(A[i] *(sum_a)) %mod
ans %=mod
print(ans) |
p02572 | s280009003 | Accepted | N = int(input())
A = list(map(int, input().split()))
ans = 0
mod = pow(10,9)+7
B = []
x = 0
for i in range(N-1):
x += A[i]
x %= mod
B.append(x)
ans = 0
for i in range(1,N):
ans += A[i]*B[i-1]
ans %= mod
print(ans)
|
p02572 | s761990009 | Accepted | N = int(input())
l = list(map(int,input().split()))
Sum = sum(l)
ans = 0
for i in range(N-1):
Sum -= l[i]
ans += Sum*(l[i])
ans %= (10**9 + 7)
print(ans)
|
p02572 | s971123657 | Accepted | def resolve():
n = int(input())
a = list(map(int, input().split()))
ans = 0
mod = (10 ** 9) + 7
csum = sum(a)
for i in range(n):
csum -= a[i]
ans += a[i] * csum
ans = int(ans % mod)
print(ans)
resolve()
|
p02572 | s059128944 | Accepted | N = int(input())
A = list(map(int, input().split()))
MOD = 10**9 + 7
S = 0
ans = 0
for a in A:
ans = (ans + a * S) % MOD
S += a
print(ans)
|
p02572 | s518501837 | Accepted | n=int(input())
a=[int(x) for x in input().split()]
b=[0]*n
b[0]=a[0]
for i in range(n-1):
b[i+1]=b[i]+a[i+1]
c=0
for j in range(n-1):
c+=a[j]*(b[n-1]-b[j])
print(c%(10**9+7)) |
p02572 | s635351320 | Accepted | n,*a=map(int,open(0).read().split())
b=sum(map(lambda x:x*x,a))
mod=10**9+7
ans=(sum(a)**2-b)//2
print(ans%mod)
|
p02572 | s170117538 | Accepted | def main():
n = int(input())
a = [int(v) for v in input().split()]
m = 1000000007
ans = 0
ss = sum(a[1:])
for i in range(n-1):
ans += a[i]*ss
ss -= a[i+1]
ans %= m
print(ans)
main() |
p02572 | s242749899 | Accepted | from itertools import accumulate
n = int(input())
a = list(map(int, input().split()))
sa = list(accumulate(a))
mod = 10 ** 9 + 7
ans = 0
for i in range(n - 1):
ans += a[i] * (sa[-1] - sa[i])
ans %= mod
print(ans)
|
p02572 | s555609415 | Accepted | N=int(input())
An=list(map(int,input().split()))
mod=10**9+7
s=sum(An)
S=0
num = 0
for i in range(N):
num += An[i]
S += (An[i]*(s-num))
print(S%mod) |
p02572 | s192634868 | Accepted | mod = int(1e9 + 7)
def pw(b, ex):
if ex == 0: return 1
if ex == 1: return b
if ex & 1: return b % mod * pw((b*b) % mod, ex >> 1) % mod
return pw((b*b) % mod, ex >> 1) % mod
n = int(input())
x = list(map(int,input().split()))
st = 0
en = 0
for i in x:
st = (st + i) % mod
en = (en + (i * i) % mod) % mod
st *= st
ans = int((st - en + mod) % mod)
ans = int(ans * int(pw(2, mod - 2)) % mod) % mod
print (int(ans)) |
p02572 | s077736435 | Accepted | def li():
return [int(x) for x in input().split()]
N = int(input())
A = li()
d = 10**9 + 7
B = [A[i] % d for i in range(len(A))]
s = 0
s2 = 0
for i in range(len(B)):
s += B[i]
s = s
s2 += B[i] ** 2
s2 = s2
ans = ((s**2 - s2) // 2) % d
print(ans) |
p02572 | s563679756 | Accepted | n=int(input())
*a,=map(int,input().split())
b=[x**2 for x in a]
mod=10**9+7
print(((sum(a)**2-sum(b))//2)%mod) |
p02572 | s546319299 | Accepted | def main():
n = int(input())
a_list = list(map(int, input().split()))
mod = 10 ** 9 + 7
x = 0
ans = 0
for i in range(1, n):
x = (x + a_list[i - 1]) % mod
ans = (ans + a_list[i] * x) % mod
print(ans)
if __name__ == "__main__":
main()
|
p02572 | s193720154 | Accepted | #!/usr/bin/env python3
N = int(input())
A = list(map(int, input().split()))
mod = 10 ** 9 + 7
s = sum(A)** 2
a = 0
for i in A:
a += (i ** 2)
ans = (s - a) // 2
ans = ans % mod
print(ans)
|
p02572 | s468097888 | Accepted | n=int(input())
a=list(map(int,input().split()))
mod=1000000007
sum_a=sum(a)
ans=0
for i in range(n):
temp=(sum_a-a[i])*a[i]
ans+=temp
print((ans//2)%mod)
|
p02572 | s839458477 | Accepted | #!/usr/bin/env python3
def main():
_ = int(input())
A = [int(x) for x in input().split()]
mod = 10 ** 9 + 7
lst = [sum(A)]
for j in A:
lst.append(lst[-1] - j)
ans = 0
for index, i in enumerate(A):
ans += i * lst[index + 1] % mod
print(ans % mod)
if __name__ == '__main__':
main()
|
p02572 | s481999559 | Accepted |
N=int(input())
A=list(map(int,input().split()))
mod=10**9+7
sumA=sum(A)
ans=0
for i in range(N):
ans+=(A[i]*(sumA-A[i]))
ans=ans//2
print(ans%mod)
|
p02572 | s067219465 | Accepted | n = int(input())
a = list(map(int,input().split()))
sum_a = sum(a)
result = 0
for i in range(n):
result += a[i] * (sum_a - a[i])
print((result)//2 %(10**9+7)) |
p02572 | s633818628 | Accepted | N=int(input())
A=list(map(int, input().split()))
MOD=1000000007
s=0
for i in range(1,N):
s+=A[i]
s%=MOD
ans=0
for i in range(N-1):
ans+=A[i]*s
ans%=MOD
s-=A[i+1]
s%=MOD
print(ans%MOD) |
p02572 | s905735111 | Accepted | n = int(input())
al = list(map(int, input().split()))
ans = sum(al)**2
for a in al:
ans -= a**2
mod = 10**9+7
print((ans//2)%mod) |
p02572 | s932264108 | Accepted | mod = 10**9 + 7
n=int(input())
s=list(map(int,input().split()))
s2=sum(map(lambda x: x ** 2,s))
ans=(((sum(s))**2)-(s2))//2%mod
print(ans) |
p02572 | s817235349 | Accepted | n = int(input())
A = list(map(int, input().split()))
sum_A = sum(A)
ans = 0
for i in range(n-1):
sum_A -= A[i]
ans += A[i] * sum_A
ans %= 10**9+7
print(ans) |
p02572 | s027366238 | Accepted | N = int(input())
A = list(map(int, input().split()))
ans = 0
m = 1000000007
s = 0
for i in range(N):
ans += A[i] * s
s += A[i]
print(ans % m)
|
p02572 | s487276219 | Accepted | N = int(input())
A = [int(a) for a in input().split()]
mod = 10**9 + 7
print(((sum(A)**2 - sum([i**2 for i in A]))//2) % mod) |
p02572 | s724250222 | Accepted | n = int(input())
a = list(map(int, input().split()))
answer = 0
mod = 10**9 + 7
total_sum = sum(a)
for idx in range(n - 1):
total_sum -= a[idx]
answer += a[idx] * total_sum
print(answer % mod) |
p02572 | s545153514 | 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 = (ans + S*A[i])%MOD
print(ans) |
p02572 | s019389114 | Accepted | n = int(input())
a = list(map(int, input().split()))
all_sum = (sum(a) ** 2)
diff = [(a[i] ** 2) for i in range(n)]
ans = (all_sum - sum(diff)) // 2
print(ans % (10 ** 9 + 7)) |
p02572 | s488782898 | Accepted | N = int(input())
A = list(map(int, input().split()))
mod = 1000000007
S = 0
_sum = 0
for i in range(N):
S += A[i]
S %= mod
for i in range(N):
S -= A[i]
if S<0:
S += mod
_sum += A[i]*S
_sum %= mod
print(_sum) |
p02572 | s126353425 | Accepted | nn = int(input())
aa = list(map(int, input().split()))
bb = [0]*(nn-1)
mysum = sum(aa)
mydiff = 0
for i in range(1,nn):
mydiff += aa[i - 1]
bb[i-1] = mysum - mydiff
finalsum = 0
for i in range(nn-1):
finalsum += aa[i]*bb[i]
finalsum = finalsum % (10**9 + 7)
print(finalsum) |
p02572 | s934105839 | Accepted | D = 10 ** 9 + 7
N = int(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 | s011855489 | Accepted | N=int(input())
A=list(map(int,input().split()))
s=sum(A)
res=0
for i in range(N-1):
s-=A[i]
res+=A[i]*s
print(res%(10**9+7)) |
p02572 | s986507831 | Accepted | n = int(input())
an = list(map(int,input().split()))
mod = 10**9 + 7
total =sum(an)
ans = 0
z = an[0]
for x in range(n-1):
nokori = total-z
ans += an[x] * nokori % mod
z += an[x+1]
ans = ans % mod
print(ans)
|
p02572 | s793976692 | Accepted | n = int(input())
a = list(map(int, input().split()))
k = 0
num = sum(a)
import math
for i in range(n):
reje = num - a[i]
k += reje * a[i]
x = k//2
t = 10 ** 9 + 7
ans = x % t
print(ans)
|
p02572 | s699025864 | Accepted | #C
N = int(input())
A = list(map(int, input().split()))
result = sum(A)**2
for i in A:
result -= i**2
print((result//2)%1000000007) |
p02572 | s614047258 | Accepted | n=int(input())
arr=list(map(int,input().split()))
s=sum(arr)
ans=0
m=10**9+7
c=0
for i in arr:
c+=i
ans+=i*(s-c)
ans%=m
print(ans) |
p02572 | s833447700 | Accepted | N = map(int, input())
An = list(map(int, input().split()))
mnum = 10 ** 9 + 7
CumSum = An[0]
answer = 0
for i in range(1, len(An)):
answer = (answer + CumSum * An[i])
CumSum = (CumSum + An[i])
print(answer%mnum) |
p02572 | s766356922 | Accepted | n = int(input())
arr = [int(x) for x in input().split()]
arr.insert(0,0)
prefix = [0 for x in range(n+1)]
for i in range(1,n+1):
prefix[i] = prefix[i-1]+arr[i];
ans = 0
mod = int(1e9+7)
for i in range(1,n):
ans += arr[i]*(prefix[n]-prefix[i])
print(ans%mod) |
p02572 | s436095879 | Accepted | n = int(input())
a = list(map(int, input().split()))
t = 0
r = 0
mod = 10**9+7
for i in range(n-1, 0, -1):
r += a[i]
t += a[i-1]*r
print(t%mod) |
p02572 | s445824953 | Accepted | n=int(input())
a=list(map(int,input().split()))
s=sum(a)
ans=0
for i in range(n-1):
s-=a[i]
ans+=a[i]*s
if ans>(10**9+7):
ans=ans%(10**9+7)
print(ans) |
p02572 | s071050439 | Accepted | import sys
def input():
return sys.stdin.readline()[:-1]
def main():
n = int(input())
a = list(map(int,input().split()))
s = sum(a)
ans = 0
for i in range(n):
s = s - a[i]
ans = ans + a[i] * s
print(ans % (10 ** 9 + 7))
if __name__ == "__main__":
main() |
p02572 | s830942180 | Accepted | N = int(input())
A = list(map(int, input().split()))
MOD = 1000000007
sum = 0
for i in range(N):
sum = sum + A[i]
res = 0
for i in range(N):
sum = sum - A[i]
res = res + (A[i] % MOD * sum % MOD)
print(res % MOD) |
p02572 | s018111596 | Accepted | N = int(input())
A = list(map(int,input().split()))
B = [0]
b = 0
mod = 10**9 + 7
for i in range(N):
b+=A[i]
b%=mod
B.append(b)
ans = 0
for i in range(N):
ans += (mod+B[N]-B[i+1])*A[i]
ans %= mod
print(ans) |
p02572 | s657123196 | Accepted | n=int(input())
c = list(map(int, input().rstrip().split()))
ans=0
b=10**9+7
sum1=0
for i in range(n):
ans=(ans+c[i]*sum1)%b
sum1=(sum1+c[i])%b
print(ans) |
p02572 | s420086840 | Accepted | from collections import deque
N = int(input())
A = list(map(int, input().split()))
#N=3
#A=[1,2,3]
q=deque(A)
#print(q)
ans=0
sums=sum(q)
#print(sums)
for i in range(N-1):
qwe=q.popleft()
ans+=qwe *(sums-qwe)
sums-=qwe
print(ans%(10**9+7)) |
p02572 | s481231293 | Accepted | N = int(input())
A = [int(v) for v in input().split()]
MOD = int(1e9 + 7)
S = sum(A)
SQ = S * S
IS = sum(a*a for a in A)
print(((SQ - IS) // 2) % MOD) |
p02572 | s142752644 | Accepted | N = int(input())
A = list(map(int, input().split()))
M = 0
sum = 0
for i in range(N):
sum += A[i]
for i in range(N-1):
sum = sum - A[i]
M += A[i] * sum
if M > 10 ** 9 + 7:
M = M % (10 ** 9 + 7)
print(M) |
p02572 | s992698178 | Accepted | n = int(input())
a= list(map(int, input().split()))
s=sum(a)
INF=1000000007
ans=0
for i in range(n-1):
s-=a[i]
ans+=a[i]*s
ans%=INF
print(ans)
|
p02572 | s044780055 | Accepted | LI = lambda: list(map(int, input().split()))
N = int(input())
A = LI()
MOD = 10 ** 9 + 7
def modinv(x):
return pow(x, MOD - 2, MOD)
def main():
s = sum(A) % MOD
ans = s * s % MOD
for a in A:
ans = (ans - a ** 2) % MOD
ans = ans * modinv(2) % MOD
print(ans)
if __name__ == "__main__":
main()
|
p02572 | s016744114 | Accepted | import numpy as np
N = int(input())
A = list(map(int ,input().split()))
sum=0
ans=0
for i in range (0,N-1):
sum=sum+A[i]
sum=sum%(1000000000+7)
ans=ans+sum*A[i+1]
ans=ans%(1000000000+7)
print(ans) |
p02572 | s362225368 | Accepted | n=int(input())
l=list(map(int,input().split()))
s=sum(l)
su=0
for i in range(n):
s=s-l[i]
s=s%1000000007
su=su+(l[i]*s)
su=su%1000000007
print(su)
|
p02572 | s626171161 | Accepted | import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
def main():
N = int(readline())
A = [int(i) for i in readline().split()]
K = int(1e9)+7
acum = [0]
for i in range(N):
acum.append(acum[i]+A[i])
ans = 0
for i in range(N):
ans += A[i]*(acum[N]-acum[i+1])
ans %= K
print(ans)
if __name__ == '__main__':
main()
|
p02572 | s404139665 | Accepted | N = int(input())
A = list(map(int, input().split()))
MOD = 1000000007
s = sum(A)
ans = 0
for i in range(N):
s -= A[i]
ans += A[i] * s
print(ans % MOD)
|
p02572 | s793697017 | Accepted | n = int(input())
a = list(map(int,input().split()))
max = (10 ** 9) + 7
#入力配列の総和
line = 0
for i in range (n):
line += a[i]
#a11, a22, ...対角線要素の総和
rem = 0
for i in range(n):
rem += a[i]*a[i]
sum = ((line*line) - rem) // 2
ans = sum % max
print(ans)
|
p02572 | s052145518 | Accepted | N = int(input())
A = list(map(int, input().split()))
S = 0
ans = 0
for k in range(N):
S = S + A[k]
for i in range(N-1):
S = S - A[i]
ans = ans + S * A[i]
ans = ans % (10**9 + 7)
print(ans)
|
p02572 | s306994438 | Accepted |
from itertools import accumulate
N = int(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 | s047397146 | Accepted | import sys
stdin = sys.stdin
def ns(): return stdin.readline().rstrip()
def ni(): return int(stdin.readline().rstrip())
def nm(): return map(int, stdin.readline().split())
def nl(): return list(map(int, stdin.readline().split()))
def main():
n = ni()
A = nl()
mod = 10 ** 9 + 7
s = sum(A)
q = sum([a ** 2 for a in A])
ans = (((s * s) - q)) // 2
print(int(ans % mod))
if __name__ == '__main__':
main()
|
p02572 | s206413071 | Accepted | mod = 10 ** 9 + 7
n = int(input())
a = list(map(int, input().split()))
s = sum(a)
ans = 0
for i in a:
s -= i
s %= mod
ans += i * s
ans %= mod
print(ans) |
p02572 | s743788912 | Accepted | N = int(input())
A = list(map(int, input().split()))
mod = 10**9 + 7
s = sum(A)
ans = 0
for i, a in enumerate(A):
s -= a
ans = (ans + s * a) % mod
print(ans) |
p02572 | s142635224 | Accepted | N = int(input())
A = list(map(int, input().split()))
reversed_cumsum = []
tmp = 0
for i in range(N):
tmp += A[N - 1 - i]
reversed_cumsum.append(tmp)
cumsum = reversed_cumsum[::-1]
ans = 0
for i in range(N - 1):
ans = (ans + A[i] * cumsum[i + 1]) % (10 ** 9 + 7)
print(ans)
|
p02572 | s817693456 | Accepted | N = int(input())
A = list(map(int, input().split()))
a = (sum(A)**2)
b = sum([(a**2) for a in A])
print(((a-b))//2%(10**9+7)) |
p02572 | s703951258 | Accepted | MOD = 1000000007
N = int(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 | s580431937 | Accepted | N = int(input())
A = list(map(int,input().split()))
ans = 0
s = 0
def mod(x):
return int(x % int(1e+9 + 7))
for i in reversed(range(N-1)):
s += A[i+1]
s = mod(s)
ans += A[i] * s
ans = mod(ans)
print(int(ans)) |
p02572 | s549035621 | Accepted | N = int(input())
A = list(map(int, input().split()))
Asum = sum(A) % (10**9 + 7)
ans = 0
for i in range(N):
Asum = Asum - A[i]
ans += A[i]*Asum % (10**9 + 7)
ans = ans % (10**9 + 7)
print (ans) |
p02572 | s809218802 | Accepted | N = int(input())
MOD = 10**9 + 7
A_s = list(map(int, input().split()))
ruiseki = []
for i, A in enumerate(A_s):
if i == 0:
ruiseki.append(A)
continue
ruiseki.append(ruiseki[i-1]+A)
answer = 0
for i, r in enumerate(ruiseki):
answer += (A_s[i] * (ruiseki[N-1]-ruiseki[i]))
answer %= MOD
print(answer) |
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