leetcode 110. 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.

解

/**
* 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(maxDepth(root.left)- maxDepth(root.right))>1){
return false;
}

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

public  int maxDepth(TreeNode root){
if(root==null)
return 0;

return Math.max(maxDepth(root.left), maxDepth(root.right))+1;
}
}