Cod sursa(job #430822)
Utilizator | Data | 31 martie 2010 13:20:13 | |
---|---|---|---|
Problema | Medie | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.41 kb |
#include<cstdio>
using namespace std;
int n,a[10001],frecv[10001],i,j,x.nr;
int main()
{
freopen("medie.in","r",stdin);
freopen("medie.out","w",stdout);
scanf("%d\n",&n);
for(i=1;i<=n;i++) scanf("%d\n",&a[i]),frecv[a[i]]++;
for(i=1;i<n;i++)
for(j=i+1;j<=n;j++)
{
x=a[j]+a[i];
if((x&1)==0)
{
x=(a[j]+a[i])>>1;
nr+=frecv[x];
if(a[i]==x) nr-=2;
}
}
printf("%d\n",nr);
return 0;
}