Leetcode 110 Balanced Binary Tree

triplebee

发布于 2018-01-12 14:56:16

3990

发布于 2018-01-12 14:56:16

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.

判断树是否是平衡的。

注意平衡树的定义，每一个点的左右子树高度差不超过1，并不是叶子结点的最大深度和最小深度不超过1.

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int dfs(TreeNode* root,bool& res)
    {
        if(!root) return 0;
        int a=dfs(root->left,res)+1;
        int b=dfs(root->right,res)+1;
        if(abs(a-b)>1) res=false;
        return max(a,b);
    }
    bool isBalanced(TreeNode* root) {
        bool res=true;
        dfs(root,res);
        return res;
    }
};

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原始发表：2016-10-12 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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