Cod sursa(job #2691049)
Utilizator | daniel guba un_fes_galben | Data | 26 decembrie 2020 20:25:53 |
---|---|---|---|
Problema | Numarare triunghiuri | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.87 kb |
#include <fstream>
#include <algorithm>
using namespace std;
int v[805];
int main()
{
ifstream fin("nrtri.in");
ofstream fout("nrtri.out");
int n;
fin>>n;
for(int i=1;i<=n;i++)
{
fin>>v[i];
}
sort(v+1,v+n+1);
int st,dr,mij,val,cnt=0;
for(int i=1;i<=n-2;i++)
{
for(int j=i+1;j<=n-1;j++)
{
int sum=v[i]+v[j];
st=j+1;dr=n;val=-1;
while(dr>=st)
{
mij=(dr+st)/2;
if(v[mij]<=sum)
{
val=mij;
st=mij+1;
}
else
{
dr=mij-1;
}
}
if(val!=-1)
{
cnt+=val-j;
}
}
}
fout<<cnt<<'\n';
return 0;
}