【LeetCode】Balanced Binary Tree

http://oj.leetcode.com/problems/balanced-binary-tree/

 

http://blog.csdn.net/fightforyourdream/article/details/18693131

 

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.

 

/**
 * 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) {
        if (root == null) {
            return true;
        }

        if (Math.abs(depth(root.left) - depth(root.right)) > 1) {
            return false;
        }

        return isBalanced(root.left) && isBalanced(root.right);
    }

    private int depth(TreeNode root) {
        if (root == null) {
            return 0;
        }
        return 1 + Math.max(depth(root.left), depth(root.right));
    }
}