leetcode--Balanced Binary Tree

Given a binary tree, determine if it is height-balanced.

For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees ofevery node never differ by more than 1.

题意：判断一棵树是否是平衡二叉树。

分类：二叉树

解法1：计算递归左右子树的深度，比较这两个深度，如果相等或者相差1，则递归判断左右子树是否平衡。

如果不符合平衡二叉树条件，则返回假。

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public boolean isBalanced(TreeNode root) {if(root==null) return true;int dis = Math.abs(getDepth(root.left)-getDepth(root.right));if(dis>=0&&dis<=1){return isBalanced(root.left)&&isBalanced(root.right);}return false;    }public int getDepth(TreeNode p){if(p==null) return 0;else{int left = getDepth(p.left);int right = getDepth(p.right);return left>right?left+1:right+1;}}}