110. Balanced Binary Tree

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.

Solution

/**
 * 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) {
        int height = height(root);
        if (height == -1) return false;
        return true;
    }

    public int height(TreeNode node) {
        if (node == null) return 0;

        int left = height(node.left);
        int right = height(node.right);

        if (left == -1 || right == -1)
            return -1;

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

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

}