Cod sursa(job #1293966)
Utilizator | Data | 16 decembrie 2014 20:14:22 | |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.63 kb |
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int n,i,v[805],mid,p,u,sol,j;
int main(){
fin>>n;
for(i=1;i<=n;i++){
fin>>v[i];
}
sort(v+1,v+n+1);
for(i=1;i<=n-2;i++){
for(j=i+1;j<=n-1;j++){
p=j+1;u=n;
while(p<=u){
mid=(p+u)/2;
if(v[i]+v[j]<v[mid]){
u=mid-1;
}
else{
p=mid+1;
}
}
sol=sol+u-j;
}
}
fout<<sol;
return 0;
}