Cod sursa(job #2967479)
Utilizator | Barbulescu Robert RORO123b | Data | 19 ianuarie 2023 17:58:37 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.68 kb |
#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int v[100001];
int cautbin(int st,int dr,int a, int b)
{
int rez=0;
while(st<=dr)
{
int mij=(st+dr)/2;
if( v[mij]<=a+b)
{
rez=mij;
st=mij+1;
}
else
{
dr=mij-1;
}
}
return rez;
}
int main()
{
int n,rez=0;
fin>>n;
for(int i=1; i<=n; i++)
fin>>v[i];
sort(v+1,v+n+1);
for(int i=1; i<n; i++)
{
for(int j=i+1; j<=n; j++)
rez+=cautbin(1,n,v[i],v[j])-j;
}
fout<<rez;
}