《程序员代码面试指南》第三章 二叉树问题 判断二叉树是否为搜素二叉树

题目

判断二叉树是否为搜素二叉树

java代码

package com.lizhouwei.chapter3;

/**
 * @Description:判断二叉树是否为搜素二叉树
 * @Author: lizhouwei
 * @CreateDate: 2018/4/14 23:10
 * @Modify by:
 * @ModifyDate:
 */
public class Chapter3_13 {
    public boolean isBalance(Node head) {
        if (head == null) {
            return false;
        }
        boolean[] record = new boolean[1];
        record[0] = true;
        getHight(head, 1, record);
        return record[0];
    }

    public int getHight(Node head, int level, boolean[] record) {
        if (head == null) {
            return level;
        }
        int leftDep = getHight(head.left, level + 1, record);
        if (!record[0]) {
            return level;
        }
        int rightDep = getHight(head.right, level + 1, record);
        if (!record[0]) {
            return level;
        }
        if (Math.abs(rightDep - leftDep) > 1) {
            record[0] = false;
        }
        return Math.max(leftDep, rightDep);
    }

    //测试
    public static void main(String[] args) {
        Chapter3_13 chapter = new Chapter3_13();
        Node head = new Node(1);
        head.left = new Node(2);
        head.right = new Node(3);
        head.left.left = new Node(4);
        head.left.right = new Node(5);
        head.left.left.left = new Node(8);
        head.left.left.right = new Node(9);
        head.left.right.left = new Node(10);

        System.out.print("head是否为平衡树 ：" + chapter.isBalance(head));
        System.out.println();
        Node head2 = new Node(1);
        head2.left = new Node(2);
        head2.right = new Node(3);
        head2.left.left = new Node(4);
        head2.left.right = new Node(5);
        head2.right.left = new Node(6);
        head2.right.right = new Node(7);
        System.out.print("head2是否为平衡树 ：" + chapter.isBalance(head2));
    }

}

结果