source: proiecte/pgraph/Code/Prim/apm2.c @ 129

//Author Antonio-Gabriel Sturzu

#include<stdio.h>
#include<string.h>
#include<time.h>
#include<stdlib.h>
#define inf 1001


int main()
{
        int n,cost=0,prev[200001],key[200001],i,min=0,imin=0,**mat,j;
        char viz[200001];
        clock_t time1,time2;
        FILE *f=fopen("apm2.in","r");

        fscanf(f,"%i",&n);
        mat=(int **) calloc(n*n,sizeof(int *));
        for(i=0;i<n;i++)
                mat[i]=(int *) calloc(n,sizeof(int));
        for(i=0;i<n;i++)
        {
                for(j=0;j<n;j++)
                        fscanf(f,"%i",&mat[i][j]);
        }
        fclose(f);
        
        memset(viz,0,sizeof(viz));
        time1=clock();
        key[0]=0;
        for(i=1;i<n;i++)
                key[i]=inf;

        for(;;)
        {
                min=inf;
                for(i=0;i<n;i++)
                {
                        if(viz[i]==0 && key[i]<min)
                        {
                                min=key[i];
                                imin=i;
                        }
                }
                if(min==inf)
                        break;
                viz[imin]=1;
                cost+=min;
                for(i=0;i<n;i++)
                {
                        if(viz[i]==0 && mat[imin][i]<key[i])
                        {
                                prev[i]=imin;
                                key[i]=mat[imin][i];
                        }
                } 
        }
        time2=clock();
        printf("Au trecut %f secunde \n",(double)(time2-time1)/CLOCKS_PER_SEC);
        f=fopen("apm2.out","w");
        fprintf(f,"%i\n",cost);
        fprintf(f,"%i\n",n-1);
        for(i=1;i<n;i++)
                fprintf(f,"%i %i\n",prev[i]+1,i+1);
        fclose(f);
        for(i=0;i<n;i++)
                free(mat[i]);
        free(mat);
        return 0;
}