HDU 1213

并查集的复习水题

#include <stdio.h>#include <iostream>using namespace std;#define LEN 10000int p[LEN];void init(int n) {int i;for(i = 1; i <= n; i++) {p[i] = i;}}int find(int x) {return p[x] == x ? x : (p[x] = find(p[x]));}void make_set(int px, int py) {if(px == py) {return;}p[px] = py;}int main() {int files;int i, j;scanf("%d", &files);while(files--) {int n, m;scanf("%d%d", &n, &m);init(n);for(i = 0; i < m; i++) {int a, b;scanf("%d%d", &a, &b);int t1 = find(a);int t2 = find(b);if(t1 != t2) {make_set(t1, t2);}}int ans = 0;for(i = 1; i <= n; i++) {if(i == p[i]) {ans++;}}printf("%d\n", ans);}return 0;}