Cod sursa(job #655928)

Utilizator vladtarniceruVlad Tarniceru vladtarniceru Data 3 ianuarie 2012 17:14:47
Problema Triplete Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.76 kb
#include <fstream>
using namespace std;

int n, m, sol;
struct {int x, y;} v[66000];
int a[4100][130];

inline int biti(int a)
{
    int nr = 0;
    while (a)
    {
        ++nr;
        a = a & (a - 1);
    }
    return nr;
}
int main()
{
    ifstream f("triplete.in");
    ofstream g("triplete.out");

    f >> n >> m;
    for (int i = 1; i <= m; ++i)
    {
        f >> v[i].x >> v[i].y;
        a[v[i].x][v[i].y >> 5] |= (1 << (v[i].y & 31));
        a[v[i].y][v[i].x >> 5] |= (1 << (v[i].x & 31));
    }

    for (int i = 1; i <= m; ++i)
    {
        int nr = i >> 5;
        for (int j = 0; j <= i; ++j)
            sol = sol + biti(a[v[i].x][j] & a[v[i].y][j]);
    }

    g << sol / 3 << '\n';
    g.close();
    return 0;
}