leetcode -- Balanced Binary Tree TODO

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 everynode never differ by more than 1.

 [解题思路]

检查每个node是否是balanced，大数据集挂掉了

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public boolean isBalanced(TreeNode root) {
        // Start typing your Java solution below
        // DO NOT write main() function
        if(root == null){
            return true;
        }
        
        return checkBalance(root);
    }
    
    public boolean checkBalance(TreeNode node){
        if(node == null){
            return true;
        }
        int left = getDepth(node.left);
        int right = getDepth(node.right);
        if(Math.abs(left - right) > 1){
            return false;
        }
        return checkBalance(node.left) && checkBalance(node.right);
    }
    
    public int getDepth(TreeNode node){
        if(node == null){
            return 0;
        }
        int left = getDepth(node.left);
        int right = getDepth(node.right);
        return Math.max(left, right) + 1;
    }
}