제출 #9838

#	제출 시각UTC-0	아이디	문제	언어	결과	실행 시간	메모리
9838	2014-10-01 13:57:27	effserv	Uniting (kriii2_U)	C++98	1 / 4	12 ms	1088 KiB

U

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#include <cstdio>
using namespace std;
typedef long long ll;
int main()
{
  int N;
  scanf("%d", &N);
  ll a;
  scanf("%lld", &a);
  ll A = (ll)a;
  ll C = 0;
  for (int i = 0; i < N - 1; i++)
  {
    scanf("%lld", &a);
    C += A*a;
    A += a;
  }
  printf("%lld\n0", C);
  return 0;
}
 
 
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• Subtask 1: 1 / 4