HDOJ 1232 并查集
并查集:
#include <cstdio> using namespace std; const int cityNum = 1000 ; int city[cityNum]; int N,M; int total; void init(){ for(int i=1;i<=N;i++){ city[i] = i; } } int findSet(int x){ int tmp = x; do{ tmp = city[tmp]; }while(tmp != city[tmp]); city[x] = tmp; return tmp; } void unionSet(int x,int y){//Y->X int xP = findSet(x); int yP = findSet(y); if(xP != yP){ total--; city[yP] = xP; city[y] = xP; } } int main(){ int city1,city2; while(scanf("%d %d",&N,&M) && N){ total = N-1; init(); for(int i=0;i<M;i++){ scanf("%d %d",&city1,&city2); unionSet(city1,city2); } printf("%d\n",total); } return 0; }