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;
    }
}