并查集模板

#include<cstdio>

#define MAX 1000
struct UnionFind
{
    int fa[MAX];

    void make_set()//初始化
    {
        for (int i = 0; i < MAX; i++)fa[i] = i;
    }

    int find_set(int x)//查
    {
        return x == fa[x] ? x : fa[x] = find_set(fa[x]);
    }

    void union_set(int a, int b)//合并
    {
        int x = find_set(a);
        int y = find_set(b);
        if (x != y)
        {
            fa[y] = x;
        }
    }
};
int main()
{

}

[map版]

#include<cstdio>
#include<map>
using namespace std;
struct UnionFind
{
    map<int,int>mp;

    UnionFind()
    {
        mp.clear();
    }

    int find_set(int x)//查
    {
        return x == mp[x] ? x : mp[x] = find_set(mp[x]);
    }

    void union_set(int a, int b)//合并
    {
        int x = find_set(a);
        int y = find_set(b);
        if (x != y)
        {
            mp[y] = x;
        }
    }
};

[可计数]

struct UnionFind
{
    int fa[MAX];
    int num[MAX];
    UnionFind()
    {
        make_set();
    }
    void make_set()//初始化
    {
        for (int i = 0; i < MAX; i++)
        {
            fa[i] = i;
            num[i] = 1;
        }
    }

    int find_set(int x)//查
    {
        return x == fa[x] ? x : fa[x] = find_set(fa[x]);
    }

    void union_set(int a, int b)//合并
    {
        int x = find_set(a);
        int y = find_set(b);
        if (x != y)
        {
            fa[y] = x;
            num[x] += num[y];
        }
    }
};