并查集-hdu畅通工程

#include "stdio.h"
int bin[1002];

int findx(int x)
{
    int r,j,i;
    r = x;
    while (bin[r] != r)
        r = bin[r];
    i = x;
    while (i != r)
    {
        j = bin[i];
        bin[i] = r;
        i = j;
    }
    return r;
}

void merge(int x,int y)
{
    int fx,fy;
    fx = findx(x);
    fy = findx(y);
    if(fx != fy)
        bin[fx] = fy;
}

int main()
{
    int n,m,i,x,y,count;
    while(scanf("%d",&n),n)
    {
        for(i=1; i<=n; i++)
            bin[i] = i;
        for(scanf("%d",&m); m>0; m--)
        {
            scanf("%d %d",&x,&y);
            merge(x,y);
        }
        for(count=-1, i=1; i<=n; i++)
            if(bin[i] == i)
                count ++;
        printf("%d\n",count);
    }
}