LeetCode: Balanced Binary Tree

题目链接：https://leetcode.com/problems/balanced-binary-tree/

题目：

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.

题意：判断一棵树是否是平衡树

分析：比较左右子树的深度，如果二者深度差大于1则返回false，不然就继续判断左右子树是否平衡

代码：

/**
 * 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;
        
        if(Math.abs(getDeepth(root.left, 1) - getDeepth(root.right, 1)) > 1) {
            return false;
        } else {
            return isBalanced(root.left) && isBalanced(root.right);    
        }
    }
    
    public int getDeepth(TreeNode root, int curDep) {
        if(root == null) {
            return curDep;
        } else {
            return Math.max(getDeepth(root.left, curDep+1), getDeepth(root.right, curDep+1));
        }
    }
    
}

LeetCode: Balanced Binary Tree

原文：http://blog.csdn.net/yangyao_iphone/article/details/48031097