Leetcode no. 110

110. Balanced Binary Tree

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 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) {
return maxDepth(root)==-1 ? false : true;
}
private int maxDepth(TreeNode root){
if (root==null) return 0;
int left= maxDepth(root.left);
int right= maxDepth(root.right);
if (left==-1 || right==-1 || Math.abs(left-right)>1) return -1;
return Math.max(left,right)+1;
}
}