POJ2524 Ubiquitous Religions

#include <iostream>#include <cstdio>#include <vector>#include <algorithm>#include <cstring>#include <string>using namespace std;const int maxn = 50001;int f[maxn+10];int gn, gm;int getFather(int x) {if(x == f[x]) return x;else return f[x] = getFather(f[x]);}int main(){int Case = 0;int x, y, t1, t2;while(scanf("%d%d", &gn, &gm) == 2 && (gn || gm)) {for(int i = 1; i <= maxn; i++) f[i] = i;for(int j = 0; j < gm; j++) {scanf("%d%d", &x, &y);t1 = getFather(x);t2 = getFather(y);if(t1 != t2) f[t1] = t2;}int cnt = 0;for(int i = 1; i <= gn; i++) {if(f[i] == i) cnt++;}printf("Case %d: %d\n", ++Case, cnt);}}