Lang:G++
Edit123456789101112131415161718192021222324252627282930#include <iostream>#include <stdio.h>#include <cstring>using namespace std;int a[10000];int main(){int n;scanf("%d",&n);for(int i=0;i<n;i++)scanf("%d",&a[i]);if(n<4){printf("1\n");return 0;}int tot=0;for(int i=0;i<n-3;i++){for(int j=i+1;j<n-2;j++){for(int x=j+1;x<n-1;x++){for(int y=x+1;y<n;y++){if((a[i]+a[x])==(a[j]+a[y]))tot+=2;if((a[i]+a[y])==(a[j]+a[x]))tot+=2;if((a[i]+a[j])==(a[x]+a[y]))tot+=2;}}}}printf("%d\n",tot);return 0;}