Leetcode：110. Balanced Binary Tree（JAVA）

【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.

【思路】

递归求左右子树深度，进而递归判断左右子树

/**
* 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;
}
}