Submission #2705

#	Time	Username	Problem	Language	Result	Execution time	Memory
2705		hana5505	지우개 (GA4_eraser)	C++98	100 / 100	24 ms	3432 KiB

eraser

#include<stdio.h>
#include<algorithm>
using namespace std;
int ar[100001];
int aa[100001];
long long g1[100001];
long long g2[100001];
long long ab(long long k){
    return (k+2000000014)%2000000014;
}
int main()
{
    int n,i,sz=0;
    long long sum1=0,sum2=0,ans=0;
 
    scanf("%d",&n);
 
    for(i=1;i<=n;i++)
        scanf("%d",&ar[i]);
 
    sort(ar+1,ar+n+1);
 
    for(i=1;i<=n;i++){
        if(!aa[ar[i]]){
            g1[++sz]=(long long)ar[i];
            aa[ar[i]]=1;
        }
        g2[sz]++;
    }
 
    for(i=2;i<=sz;i++){
        sum1=ab(sum1+ab(g1[i]*g2[i]));
        sum2=ab(sum2+ab( ab(g1[i]*g2[i])*ab(g1[i]*g2[i]) ));
    }
 
    for(i=1;i<=sz-2;i++){
        ans=ab( ans+ab( ab(ab(g1[i]*g2[i])* ab(sum1*sum1-sum2) ))/2 );
        sum1=ab(sum1-ab(g1[i+1]*g2[i+1]));
        sum2=ab(sum2-ab( ab(g1[i+1]*g2[i+1])*ab(g1[i+1]*g2[i+1]) ));
    }
 
    printf("%lld",ans%1000000007);
}

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