题解 | #判断是不是平衡二叉树#

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 * }
 */
public class Solution {
    public boolean IsBalanced_Solution(TreeNode root) {
        if (root == null) {
            return true;
        }
        if (Math.abs(depth(root.left) - depth(root.right)) > 1) {
            return false;
        } else {
            return IsBalanced_Solution(root.left) && IsBalanced_Solution(root.right);
        }
    }
    public static int depth(TreeNode root) {
        if (root == null) {
            return 0;
        } else {
            return Math.max(depth(root.left), depth(root.right)) + 1;
        }
    }
}