LeetCode(110): Balanced Binary Tree

Posted 2020-06-17

Balanced Binary Tree: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.

题意：判断给定的二叉树是否是平衡二叉树。

思路：采用递归的方法判断坐左子树的深度和右子树的深度是否大于1，其中要编写求深度的函数。

代码：

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