Cod sursa(job #643420)
Utilizator | Data | 3 decembrie 2011 17:51:15 | |
---|---|---|---|
Problema | Medie | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.48 kb |
#include <cstdio>
#define deb(n) fprintf(stderr,"%d ",(n));
#define DN 9005
int n,v[DN],aparitii[DN];
int main()
{
freopen("medie.in","r",stdin);
freopen("medie.out","w",stdout);
int i;
scanf("%d",&n );
for(i=1; i<=n;++i) {
scanf("%d",&v[i] );
++aparitii[v[i]];
}
int rez=0;
for(i=2; i<=n;++i) for(int j=1; j<i; ++j) {
int sum=v[i]+v[j];
if(0==sum%2){
rez+=aparitii[sum/2];
if(v[i]==v[j]) rez-=2;
}
}
printf("%d",rez);
return 0;
}