对平衡二叉树的增加和删除

import java.util.ArrayList;import java.util.Scanner;public class LearnAVL {private static ArrayList<AvlNode> queue;public static void main(String[] args) {// TODO 自动生成的方法存根queue=new ArrayList<AvlNode>();Scanner read=new Scanner(System.in);String str=read.nextLine();String strr[]=str.split(" ");AvlNode root=new AvlNode(Integer.valueOf(strr[0]));System.out.println(strr.length);//测试数据for(int i=1;i<strr.length;i++){root=insert(Integer.valueOf(strr[i]),root);}root=delete(root,Integer.valueOf(strr[0]));queue.add(root);//打印树 层次遍历pfs();}public static AvlNode insert(int x,AvlNode t){if(t==null){return new AvlNode(x);}int comparaResult=t.compareTo(x);if(comparaResult>0){//小于当前值，插在左边t.left=insert(x,t.left);comparaResult=t.left.compareTo(x);if(getHeight(t.left)-getHeight(t.right)>1){if(t.left.compareTo(x)>0){t=rotateLeft(t);}else{t=doubleRotateLeft(t);}}}else if(comparaResult<0){//大于当前值，插在右边t.right=insert(x,t.right);comparaResult=t.right.compareTo(x);if(getHeight(t.right)-getHeight(t.left)>1){if(t.right.compareTo(x)<0){t=rotateRight(t);}else{t=doubleRotateRight(t);}}}else{return t;}t.height=Math.max(getHeight(t.right), getHeight(t.left))+1;return t;}private static AvlNode delete(AvlNode t,int x){if(t==null){return null;}int compareRes=t.compareTo(x);if(compareRes>0){t.left=delete(t.left,x);if(getHeight(t.right)-getHeight(t.left)>1){//右左  双旋转if(getHeight(t.right.left)>getHeight(t.right.right)){t=doubleRotateRight(t);}else{t=rotateRight(t);}}}else if(compareRes<0){t.right=delete(t.right,x);if(getHeight(t.left)-getHeight(t.right)>1){//左右  双旋转if(getHeight(t.left.right)>getHeight(t.left.left)){t=doubleRotateLeft(t);}else{t=rotateLeft(t);}}}else if(compareRes==0){t=null;}if(t!=null){t.height=Math.max(getHeight(t.left), getHeight(t.right))+1;}return t;}/** * 右旋转：将t的右节点变为根节点，想象在重力的作用下，t滑落到左边，变为左节点 * @param t 树变为不平衡的第一个节点 * @return */private static AvlNode rotateRight(AvlNode t) {AvlNode k2=t.right;t.right=k2.left;k2.left=t;t.height=Math.max(getHeight(t.left), getHeight(t.right))+1;k2.height=Math.max(getHeight(t.left), getHeight(t.right))+1;return k2;}/** * 左旋转：同右旋转 * @param t 树变为不平衡的第一个节点 * @return */private static AvlNode rotateLeft(AvlNode t) {AvlNode k2=t.left;t.left=k2.right;k2.right=t;t.height=Math.max(getHeight(t.left), getHeight(t.right))+1;k2.height=Math.max(getHeight(k2.right), getHeight(k2.left))+1;return k2;}/** * 插入左子树的右子树时旋转，具体：先让右子树向左旋转（变为一个可以单旋转的左子树，即将右边的子树整合到左边），然后左子树向右旋转 * @param t 树变为不平衡的第一个节点 * @return */private static AvlNode doubleRotateLeft(AvlNode t) {t.left=rotateRight(t.left);t=rotateLeft(t);return t;}/** * 插入右子树的左子树时旋转，具体：先让左子树向右旋转（变为一个可以单旋转的右子树，即将左边的子树整合到右边），然后右子树向左旋转 * @param t 树变为不平衡的第一个节点 * @return */private static AvlNode doubleRotateRight(AvlNode t) {t.right=rotateLeft(t.right);t=rotateRight(t);return t;}private static int getHeight(AvlNode t){return t==null?0:t.height;}private static void pfs(){AvlNode t;while(!queue.isEmpty()&&(t=queue.remove(0))!=null){System.out.println(t.element);if(t.left!=null){queue.add(t.left);}if(t.right!=null){queue.add(t.right);}}}}class AvlNode implements Comparable<Integer>{public int element,height=1;public AvlNode left,right;public AvlNode(int t){this(t,null,null);}public AvlNode(int t,AvlNode left ,AvlNode right){element=t;this.left=left;this.right=right;}@Overridepublic int compareTo(Integer o) {// TODO 自动生成的方法存根if(element>o){return 1;}else if(element<o){return -1;}return 0;}}