Cod sursa(job #230177)
Utilizator | Carabet Cosmin Andrei cosmin79 | Data | 13 decembrie 2008 10:49:59 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 45 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.45 kb |
#include <algorithm>
#include <stdio.h>
using namespace std;
int main()
{
freopen("nrtri.in","r",stdin);
freopen("nrtri.out","w",stdout);
int i,n,a[801],j,t,s=0;
int sum[30005]={0};
scanf("%d",&n);
for (i=1; i<=n; i++)
{
scanf("%d",&a[i]);
++sum[a[i]];
}
for(i=1;i<=30000;++i)
sum[i]+=sum[i-1];
sort (a+1, a+n+1);
for (i=1; i<=n-2; i++)
for (j=i+1; j<=n-1; j++)
s+=sum[a[i]+a[j]]-j;
printf("%d",s);
return 0;
}