Cod sursa(job #3214061)
Utilizator | Bora Ioan Alexandru Alexbora13 | Data | 13 martie 2024 19:01:04 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.55 kb |
#include <bits/stdc++.h>
#define MAX 800
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int n, ans;
int v[MAX+1];
int main()
{
fin >> n;
for(int i=1; i<=n; i++)
fin >> v[i];
sort(v+1,v+1+n);
for(int i=1; i<=n; i++)
{
for(int j=i+1; j<=n; j++)
{
int sum = v[i]+v[j];
int st = lower_bound(v+1,v+1+n,sum)-v;
int dr = upper_bound(v+1,v+1+n,sum)-v-1;
ans+=dr-st+1;
}
}
fout << ans;
return 0;
}