首页 > 代码库 > leetcode------Balanced Binary Tree

leetcode------Balanced Binary Tree

标题:

Balanced Binary Tree

通过率:32.3%
难度:简单

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.

平衡二叉树。这个可以由二叉树深度来计算,再二叉树深度计算中每次进行深度比较取深度较深的一个,那么平衡二叉树再比较深度时就是A-B绝对值超过一的话就不是二叉树了。立马返回-1 ,当左右子树有一边深度值是-1时立马终止,返回此树非平衡二叉树,如果A-B绝对值总是在0,1,-1三个数之中,那么继续深度递归判断,具体代码如下:

 1 /** 2  * Definition for binary tree 3  * public class TreeNode { 4  *     int val; 5  *     TreeNode left; 6  *     TreeNode right; 7  *     TreeNode(int x) { val = x; } 8  * } 9  */10 public class Solution {11     public boolean isBalanced(TreeNode root) {12         if(root==null) return true;13         if(height(root)==-1) return false;14         else return true;15         16     }17     public int height(TreeNode root){18         if(root==null) return 0;19         int depth1=0;20         int depth2=0;21         depth1=height(root.right);22         depth2=height(root.left);23         if(depth1==-1||depth2==-1) return -1;24         if((depth1-depth2>1 )||(depth1-depth2)<-1)25             return -1;26         else{27              if(depth1>depth2)28             return depth1+1;29             else30                 return depth2+1;31         }32             33     }34 }

 

leetcode------Balanced Binary Tree