并查集板子加例题

//http://poj.org/problem?id=1611
#include<bits/stdc++.h>
using namespace std;
const int maxn = 30010;
int f[maxn],num[maxn],n,m;
int find(int x) {
	return f[x] == x ? x : f[x] = find(f[x]);
}
int main() {
	while(cin >> n >> m && (n + m)) {
		for(int i = 0; i < n; i++) {
			f[i] = i;
			num[i] = 1;
		}
		while(m--) {
			int k, t;
			cin >> k >> t;
			int ft = find(t);
			while(--k) {
				int i;
				cin >> i;
				int fi = find(i);
				if(ft != fi) {
					f[fi] = ft;
					num[ft] += num[fi];
				}
			}
		}
		cout << num[find(0)] <<endl;
	}
	return 0;
}
//http://acm.hdu.edu.cn/showproblem.php?pid=1272
#include<bits/stdc++.h>
using namespace std;
const int maxn = 100010;
int f[maxn], flag, visit[maxn];
void init() {
	for(int i = 0; i< maxn; i++)
		f[i] = i, visit[i] = 0;
}
int find(int x) {
	return f[x] == x ? x : f[x] = find(f[x]);
}
void Union(int x,int y) {
	int fx = find(x);
	int fy = find(y);
	if(fx == fy)	flag = 0;
	else f[fx] = fy;
}
int main() {
	//freopen("D:\MY\ce.txt","r",stdin);
	init();
	int a,b;
	flag = 1;
	while(cin >> a >> b) {
		visit[a] = 1, visit[b] = 1;
		if(a == -1 && b == -1)
			break;
		if(a == 0 && b == 0) {
			int sum = 0;
			for(int i = 1; i < maxn; i++) {
				if(visit[i] && f[i] == i)
					sum ++;
				if(sum >= 2) {
					flag = 0;
					break;
				}
			}
			if(flag)	cout << "Yes" <<endl;
			else	cout << "No" <<endl;
			init();
			flag = 1;
			continue;
		}
		Union(a, b);
	}
	return 0;
}
//https://ac.nowcoder.com/acm/contest/1080/B
#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
int f[maxn],n,ans[maxn];
void init() {
    for(int i = 0; i < n; i++)
        f[i] = i;
}
int find(int x) {
    return f[x] == x ? x : f[x] = find(f[x]);
}
int main() {
    cin >> n;
    init();
    int t = n, temp;
    while(t--) {
        cin >> temp;
        int ft = find(temp % n);
        ans[ft] = temp;
        f[ft] = find((ft + 1) % n);
    }
    for(int i = 0; i < n; i++)
        cout << ans[i] << " ";
    cout << endl;
    return 0;
}
//https://codeforces.com/problemset/problem/1131/F
#include<bits/stdc++.h>
using namespace std;
const int maxn = 150010;
int f[maxn],n,l[maxn],r[maxn],ans[maxn];
void init() {
	for(int i = 1; i <= n; i++)
		f[i] = l[i] = r[i] = i, ans[i] = 0;
}
int find(int x) {
	return x == f[x] ? x : f[x] = find(f[x]);
}
int main() {
	int a,b;
	cin >> n;
	init();
	while(--n) {
		cin >> a >>b;
		int fa = find(a);
		int fb = find(b);
		if(fa != fb) {
			ans[r[fa]] = l[fb];
			f[fa] = fb;
			l[fb] = l[fa];
		}
	}
	for(int i = l[find(1)]; i; i = ans[i])
		cout << i << " ";
	cout <<endl;
	return 0;
}