并查集之树状数组

public class UnionTree {private int[] parent;private int[] size;//记录树的大小private int total;private int groups;public void init(int n){assert(n>0);parent = new int[n];for(int i=0; i<n; i++){parent[i] = i;}size = new int[n];for(int i=0; i<n; i++){size[i] = 1;}total = n;groups = n;}public int find(int p){assert(p>=0 && p<total);int v = parent[p];while(v != p){p = v;v = parent[p];}parent[p] = v;//路径压缩return v;}public boolean isConnected(int p1, int p2){assert(p1 != p2);assert(p1>=0 && p1<total);assert(p2>=0 && p2<total);int v1 = find(p1);int v2 = find(p2);return v1==v2 ? true : false;}public void union(int p1, int p2){int v1 = find(p1);int v2 = find(p2);if(v1 == v2){return;}//size小的树作为子树和size大的树进行合并,尽量的保持整棵树的平衡if(size[v1] < size[v2]){parent[v1] = v2;}else{if(size[v1] == size[v2]){size[v1]++;}parent[v2] = v1;}groups--;}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stub}}