Cod sursa(job #63396)
Utilizator | Data | 28 mai 2007 14:09:40 | |
---|---|---|---|
Problema | Medie | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.35 kb |
#include<stdio.h>
long nr[7001],sol,j,i,n;
int v[9001];
int main()
{
scanf("%ld",&n);
for(i=1;i<=n;i++)
scanf("%d",&v[i]);
for(i=1;i<=n;i++)
for(j=i+1;j<=n;j++)
{
if((v[i]+v[j])%2==0)
nr[(v[i]+v[j])/2] ++;
if(v[i] == v[j]) sol-=2;
}
for(i=1;i<=n;i++)
sol+=nr[v[i]];
printf("%ld",sol);
return 0;
}