balancedBinaryTree.java

// 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 {
    
    boolean balanced = true;
    
    public boolean isBalanced(TreeNode root) {
        
        height(root);
        return balanced;
        
    }
    
    private int height(TreeNode root) {
        
        if(root == null) return 0;
        
        int leftHeight = height(root.left);
        int rightHeight = height(root.right);
        
        if(Math.abs(leftHeight - rightHeight) > 1) {
            
            balanced = false;
            
        }
        
        return 1 + Math.max(leftHeight, rightHeight);
        
    }
    
}