[LeetCode] Grind 75 questions (11/75) Balanced Binary Tree

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/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public boolean isBalanced(TreeNode root) {
        if(root == null) return true;
        if(Math.abs(getHeight(root.left) - getHeight(root.right)) > 1) return false;
        return isBalanced(root.left) && isBalanced(root.right);
    }

    private int getHeight(TreeNode node) {
        if(node == null) return 1;
        return Math.max(getHeight(node.left), getHeight(node.right)) + 1;        
    }
}