Cod sursa(job #8113)

Utilizator love_for_uSpancioc Riana love_for_u Data 23 ianuarie 2007 20:21:33
Problema Triplete Scor 0
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.22 kb

#include <stdio.h>
#define NMAX 4096
#define MMAX 66000

struct per { int x, y; } V[MMAX];

int Nr[1 << 17];
int A[NMAX][ NMAX/32 ];
int i, j, N, M, a, b, cfg;
long long rez;

inline void set(int cnf,int x)
{
   A[cnf][x>>5] |= 1 << (x & 31);
}

void prep()
{
     int i;

     Nr[0] = 0;

     for (i = 1; i < 1 << 16; i++)
       Nr[i] = Nr[i >> 1] + (i&1);
}

int main()
{
     freopen("triplete.in","r",stdin);
     freopen("triplete.out","w",stdout);

     scanf("%d %d", &N, &M);

     if (N == 1) { printf("0\n"); return 0; }
     if (N == 2) { printf("0\n"); return 0; }
     if (N == 3 && M != 3) { printf("0\n"); return 0;}

     rez = 0;

     for (i = 1; i <= M; i++)
     {
          scanf("%d %d", &a, &b);

          V[i].x = a;
          V[i].y = b;

          set(a, b);
          set(b, a);
     }

     prep();

     for (i = 1; i <= M; i++)
     {
          a = V[i].x;
          b = V[i].y;

          for (j = 0; j < NMAX/32; j++)
          {
               cfg = A[a][j] & A[b][j];

               if (cfg >= (1 << 16) ) rez += Nr[cfg >> 1] + (cfg&1);
               else rez += Nr[cfg];
          }
     }

     printf("%lld\n", rez/3);

     return 0;
}