Is BST Balanced

IsBalancedBST.java

/**
 * Definition for binary tree
 * 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 (root.left == null && root.right == null) return true;
        
        int left = 0;
        int right = 0;
        if (root.left != null)
            left = getHeight(root.left);
         if (root.right != null)     
            right = getHeight(root.right);
       
        if (Math.abs(left - right) > 1){
          return false;
        }
        else{
            return isBalanced(root.left) && isBalanced(root.right);
        }
    }
    
    
    public int getHeight(TreeNode node){
        if (node == null) return 0;
        
        return Math.max(getHeight(node.left), getHeight(node.right)) + 1;
        
        
    }
    
}


//Alternate:

/**
 * Definition for binary tree
 * 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 (root.left == null && root.right == null) return true;
        
        int left = 0;
        int right = 0;
        if (root.left != null)
            left = getHeight(root.left, 1);
         if (root.right != null)     
            right = getHeight(root.right, 1);
       
        if (Math.abs(left - right) > 1){
          return false;
        }
        else{
            return isBalanced(root.left) && isBalanced(root.right);
        }
    }
    
    
    public int getHeight(TreeNode node, int level){
        if (node.left == null && node.right == null){
            return level;
        }
        
        int left = 0;
        int right = 0;
        
        if (node.left != null)
            left = getHeight(node.left, level + 1);
        
        if (node.right != null)
            right = getHeight(node.right, level + 1);
            
        return Math.max(left, right);
        
    }
}