Union_Find_set

import java.util.Scanner;/**  * ClassName:UnionFindSet <br/>  * Function: 并查集. <br/>  * Reason:   并查集. <br/>  * Date:     2013年10月14日 下午4:37:42 <br/>  * @author    * @version    * @since    JDK 1.6  * @see        */public class UnionFindSet {private int[] father;private int[] rank;/** *  * make_set:<br /> * 把每一个元素初始化为一个集合  * 初始化后每一个元素的父节点是它本身 * * @author zhangzhaoyu */public void make_set() {for (int i=0; i<father.length; i++) {father[i] = i;rank[i] = 0;}}/** *  * find_set:<br /> * 查找一个元素所在的集合，其重点是找到这个元素所在的 * 结合的祖先 * * @author zhangzhaoyu * @param x * 要查找的元素 * @return * 查找到祖先 */public int find_set_recursion(int x) {if (x != father[x]) {father[x] = find_set(father[x]);}return father[x];}/** *  * find_set:<br /> * 将查找路径的所有节点都指向根节点  * * @author zhangzhaoyu * @param x * @return */public int find_set(int x) {int k, root;root = x;while (root != father[root]) {root = father[root];}while (x != root) {k = father[x];father[x] = root;x= k;}return x;}public void union(int x, int y) {x = find_set_recursion(x);y = find_set_recursion(y);if (x == y) {return ;}if (rank[x] > rank[y]) {father[y] = x;} else if (rank[x] < rank[y]) {father[x] = y;} else {rank[y]++;father[x] = y;}}/** *  * printSet:<br /> * 打印各个数据集 * * @author zhangzhaoyu */public void print_set() {for (int i=1; i<father.length; i++) {if (father[i] == i) {System.out.print("[ ");for (int j=1; j<father.length; j++) {int z = find_set(j);if (z == i) {System.out.print(j + " ");}}System.out.println(" ]");}}}public void readData() {Scanner in = new Scanner(System.in);int n = in.nextInt();int m = in.nextInt();father = new int[n+1];rank = new int[n+1];make_set();for (int i=1; i<=m; i++) {int a = in.nextInt();int b = in.nextInt();int x = find_set_recursion(a);int y = find_set_recursion(b);union(x, y);}print_set();}public static void main(String[] args) {new UnionFindSet().readData();}}