Cod sursa(job #3247961)

Utilizator Vlad10Vlad Negut Vlad10 Data 10 octombrie 2024 08:52:27
Problema Triplete Scor 0
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.58 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin ("triplete.in");
ofstream fout ("triplete.out");
int n,m,a,b;
long long s=0;
bool f[4097][4097];
int v[4097];
long long calccomb(int n, int k){
    long long p=1;
    for(long long d=n-k+1;d<=n;d++){
        p=p*d;
    }
    p=p/2;
    return p;
}
int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++){
        fin>>a>>b;
        f[a][b]=1;
        v[b]++;
    }
    for(int i=1;i<=n;i++){
        if(v[i]>=2){
            s=s+calccomb(v[i],2);
        }
    }
    fout<<s;
    return 0;
}