Leetcode-balanced-binary-tree

题目描述

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 of every node never differ by more than 1.

判断原则是：如果左子树和右子树深度差不大于1并且左子树和右子树都是平衡二叉树，那么这棵树就是平衡的！

 * 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 leftdepth = getDepth(root.left);int rightdepth = getDepth(root.right);if(Math.abs(leftdepth - rightdepth) <= 1){return isBalanced(root.left) && isBalanced(root.right);}return false;    }    public static int getDepth(TreeNode root){if(root == null)return 0;return Math.max(getDepth(root.left)+1, getDepth(root.right)+1);}}

原理和代码对于还是比较清晰地！