Submission #2418

#	Time	Username	Problem	Language	Result	Execution time	Memory
2418		hana5505	지우개 (GA4_eraser)	C++98	46 / 100	19 ms	3620 KiB

eraser

#include<stdio.h>
int mod=1000000007;
long long ar[100001];
int aa[100001];
long long sum1[100001];
long long sum2[100001];
int main()
{
	long long s=0;
	int n,i,size=0;

	scanf("%d",&n);

	for(i=1;i<=n;i++){
		scanf("%lld",&ar[i]);
		aa[(int)ar[i]]++;
	}

	for(i=1;i<=100000;i++){
		if(aa[i])
			ar[++size]=i;
	}

	for(i=1;i<=size;i++){
		sum1[i]=( sum1[i-1]+(ar[i]*aa[ar[i]])%mod )%mod;
		sum2[i]=sum2[i-1]+(( (ar[i]*aa[ar[i]])%mod )*( (ar[i]*aa[ar[i]])%mod )%mod)%mod;
	}

	for(i=1;i<=size-2;i++){
		s+=aa[(int)ar[i]]*ar[i]*(((((sum1[size]-sum1[i])%mod)*((sum1[size]-sum1[i])%mod)-(sum2[size]-sum2[i]))/2)%mod);
		s=s%mod;
	}

	printf("%lld",s);
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 16 / 16
• Subtask 4: 17 / 17
• Subtask 5: 0 / 26
• Subtask 6: 0 / 28