Java数据结构之并查集的实现

package com.chaojilaji.book.andcheck;

public class AndCheckSet {


    public static Integer getFather(int[] father, int u) {
        if (father[u] != u) {
            father[u] = getFather(father, father[u]);
        }
        return father[u];
    }

    public static void join(int[] father,int x, int y) {
        int fx = getFather(father,x);
        int fy = getFather(father,y);
        if (fx != fy){
            father[fx] = fy;
        }
    }

    public static void main(String[] args) {
        int n = 10;
        int[] a = new int[n];
        for (int i = 0;i<n;i++){
            a[i] = i; // 初始化定义一百个集合
        }
        for (int i=0;i<n;i++){
            System.out.println(i+" "+getFather(a, i)); // 对于每个集合，父节点都是自己
        }
    }
}

public static Integer getFather(int[] father, int u) {
    if (father[u] != u) {
        father[u] = getFather(father, father[u]);
    }
    return father[u];
}

public static void join(int[] father,int x, int y) {
    int fx = getFather(father,x);
    int fy = getFather(father,y);
    if (fx != fy){
        father[fx] = fy;
    }
}

public static void main(String[] args) {
    int n = 10;
    int[] a = new int[n];
    for (int i = 0;i<n;i++){
        a[i] = i; // 初始化定义n个集合
    }
    for (int i=0;i<n;i++){
        System.out.println(i+" "+getFather(a, i)); // 对于每个集合，父节点都是自己
    }
    System.out.println("-------------------------");
    join(a,0,1); // 合并 0 和 1
    for (int i=0;i<n;i++){
        System.out.println(i+" "+getFather(a, i));
    }
    // 由于合并了0和1，所以集合变成了9个，节点0和节点1的根都是节点1
    System.out.println("-------------------------");
    join(a,2,3); // 合并 2 和 3
    for (int i=0;i<n;i++){
        System.out.println(i+" "+getFather(a, i));
    }
    // 由于合并了2和3，所以集合变成8个，节点2和节点3的根都是节点3
    System.out.println("-------------------------");
    join(a,1,3); // 合并 1 和 3
    for (int i=0;i<n;i++){
        System.out.println(i+" "+getFather(a, i));
    }
    // 由于合并了1和3，所以集合变成7个，节点0,1,2,3的根都是节点3
}