Cod sursa(job #2734242)
Utilizator | Cristi Gavrila C_R_I_S_T_I_2_3 | Data | 31 martie 2021 16:11:42 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.75 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int v[805];
int n, C, x;
int CB(int x)
{
int st=1, dr=n, mij, sol=-1;
while(st<=dr)
{
mij=(st+dr)/2;
if(x<v[mij])
{
dr=mij-1;
}
else
{
sol=mij;
st=mij+1;
}
}
return sol;
}
int main()
{
fin >> n;
for(int i=1; i<=n; i++)
{
fin >> v[i];
}
sort(v+1, v+n+1);
for(int i=1; i<=n-2; i++)
{
for(int j=i+1; j<=n-1; j++)
{
x=CB(v[i]+v[j]);
if(x!=-1)
{
C+=x-j;
}
}
}
fout << C;
return 0;
}