LeetCode——Balanced Binary Tree

Description：

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.

判断是不是二叉平衡树，递归还是递归。

/**
 * 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) {
        if(root == null)
            return true;
        int l = getDepth(root.left, 1);
        int r = getDepth(root.right, 1);
        if(Math.abs(l-r) > 1) {
            return false;
        }
        else {
            return isBalanced(root.left) && isBalanced(root.right);
        }

    }
    public int getDepth(TreeNode root, int depth) {
        if(root == null) {
            return depth;
        }
        else {
            return Math.max(getDepth(root.left, depth+1), getDepth(root.right, depth+1));
        }

    }
}