并查集

#include<stdio.h>
int n,m,parent[200010],rank[200010];

//初始化函数 
void chushihua()
{
    for (int i = 0; i <= n; i++)
    {    parent[i] = i;
        rank[i] = 1;
    }
}

//找根函数 
int  root_search(int t)
{
    while(parent[t] != t)
    {
        t = parent[t];
        rank[t]++;
    }
    return t;
}

//合并函数 
void merge(int u,int v)
{
    int t1 = root_search(u);
    int t2 = root_search(v);
    if (t1 != t2){
        if (rank[t1] > rank[t2])    parent[t2] = t1;
        else    parent[t2] = t1;
        
    }    
}

//主函数 
int main()
{
    scanf("%d%d",&n,&m);
    int k,index = 0;
    chushihua();
    for (int i = 0; i < m; i++)
    {
        scanf("%d",&k);
        if (k == 2)
        {
            int A,B;
            scanf("%d%d",&A,&B);
            A = root_search(A);
            B = root_search(B);
            if (A == B)        printf("Y
");
            else    printf("N
");
        } 
        else 
        {
            int A,B;
            scanf("%d%d",&A,&B);
            merge(A,B);
        }
    }
    return 0;
}