Submission #4127

#	Time	Username	Problem	Language	Result	Execution time	Memory
4127		pichulia	지우개 (GA4_eraser)	C++98	100 / 100	16 ms	3040 KiB

eraser

#include<stdio.h>
#include<algorithm>
#define M 1000000007
using namespace std;
long long int a[100005];
long long int s[100005];
int n, m;
int b[100005];
int main()
{
	long long int i, j, k;
	scanf("%d",&n);
	for(i=0; i<n; i++)
	{
		scanf("%lld",&j);
		b[j]++;
	}
	for(i=1; i<=100000;i++)
	{
		if(b[i]>0)
		{
			a[++m]=(i*b[i])%M;
		}
	}
	for(i=1;i<=m;i++)
		s[i]=(s[i-1]+a[i])%M;
	k=0;
	for(i=1; i<=m; i++)
	{
		j=(s[i-1]*(s[m]-s[i]))%M;
		k=(k+ j * a[i])%M;
	}
	printf("%lld\n",k);
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 16 / 16
• Subtask 4: 17 / 17
• Subtask 5: 26 / 26
• Subtask 6: 28 / 28