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  • [leetcode]Balanced Binary Tree

    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.

    算法思路:

    求出各个子树是否是平衡二叉树。为了防止多余计算,最好采取后序遍历。

    代码如下:

     1 public class Solution {
     2    public boolean isBalanced(TreeNode root) {
     3         if(root == null || (root.left == null && root.right == null))
     4             return true;
     5         if(!isBalanced(root.left) || !isBalanced(root.right))
     6             return false;
     7         int left = getHeight(root.left);
     8         int right = getHeight(root.right);
     9         if(Math.abs(right - left) > 1) return false;
    10         return true;
    11     }
    12     
    13     private int getHeight(TreeNode root){
    14         if(root == null) return 0;
    15         if(root.left == null && root.right == null) return 1;
    16         int left = 0,right = 0;
    17         if(root.left != null) left = getHeight(root.left);
    18         if(root.right != null) right = getHeight(root.right);
    19         return Math.max(left, right) + 1;
    20     }
    21 }
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  • 原文地址:https://www.cnblogs.com/huntfor/p/3883531.html
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