Cod sursa(job #2194603)
Utilizator | Mihai Lazar Mihai77 | Data | 13 aprilie 2018 20:30:33 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.6 kb |
#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int n,i=1,j,v[1000],f,d,nr;
int cb(int st,int dr,int x)
{
int rez=0,m;
while(st<=dr)
{
m=(st+dr)/2;
if(v[m]>x) dr=m-1;
else if(v[m]<=x)
{
st=m+1;
rez++;
}
}
return rez;
}
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++)
{
d=v[i]+v[j];
nr+=cb(j+1,n,d);
}
fout<<nr;
return 0;
}