题解 | #判断是不是平衡二叉树#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pRoot TreeNode类 
     * @return bool布尔型
     */
    boolean isBalance = true;
    public boolean IsBalanced_Solution (TreeNode pRoot) {
        // write code here
        TreeDepth(pRoot);
        return isBalance;
    }

    private int TreeDepth(TreeNode node){
        if(node == null){
            return 0;
        }
        int l = TreeDepth(node.left);
        if(l == -1){
            return -1;
        }
        int r = TreeDepth(node.right);
        if(r == -1){
            return -1;
        }
        if(Math.abs(l - r) > 1){
            isBalance = false;
            return -1;
        }
        return Math.max(l,r)+1;
    }
}