hdu1232 畅通工程

#include <stdio.h>#include <string.h>int father[1002],sum;//并查集int find (int k){if(father[k]!=k)father[k]=find(father[k]);return father[k];}void make(int x,int y){int f1=find(x);int f2=find(y);if(f1!=f2){father[f2]=f1;//sum++;}}int main(){int n,m,i,x,y;while(scanf("%d",&n)&&n!=0){scanf("%d",&m);memset(father,0,sizeof(father));sum=0;for(i=1;i<=n;i++)father[i]=i;for(i=0;i<m;i++){scanf("%d %d",&x,&y);make(x,y);}for(i=1;i<=n;i++){if(father[i]==i)sum++;}printf("%d\n",sum-1);//printf("%d\n",n-1-sum);}return 0;}