Cod sursa(job #66488)
Utilizator | Ionut Bogdanescu swift90 | Data | 19 iunie 2007 13:06:53 |
---|---|---|---|
Problema | Medie | Scor | 20 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.49 kb |
#include<stdio.h>
int v[7010];
int main(){
freopen("medie.in","r",stdin);
freopen("medie.out","w",stdout);
int n,i,aux,s=0,max=0,j;
scanf("%d",&n);
for(i=0;i<n;i++){
scanf("%d",&aux);
v[aux]++;
if(aux>max)
max=aux;
}
for(i=1;i<=max;i++){
if(v[i]){
if(v[i]>2)
s+=v[i]*(((v[i]-1)*(v[i]-2))/2);
for(j=1;j<i;j++){
if(v[j]){
aux=2*i-j;
if(aux<=7000)
s+=v[j]*v[aux];
}
}
}
}
printf("%d\n",s);
return 0;
}