首页 > 其他 > 详细

102. Binary Tree Level Order Traversal

时间:2019-01-13 15:56:38      阅读:150      评论:0      收藏:0      [点我收藏+]

Given a binary tree, return the level order traversal of its nodes‘ values. (ie, from left to right, level by level).

For example:
Given binary tree [3,9,20,null,null,15,7],

    3
   /   9  20
    /     15   7

 

return its level order traversal as:

[
  [3],
  [9,20],
  [15,7]
]

层次遍历

C++:
 1 /**
 2  * Definition for a binary tree node.
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 public:
12     vector<vector<int>> levelOrder(TreeNode* root) {
13         if (root == NULL)
14             return vector<vector<int>>() ;
15         vector<vector<int>> res ;
16         vector<int> level ;
17         queue<TreeNode*> q ;
18         q.push(root) ;
19         while(!q.empty()){
20             int len = q.size() ;
21             for(int i = 0 ; i < len ; i++){
22                 TreeNode* temp = q.front() ;
23                 q.pop() ;
24                 if (temp->left != NULL)
25                     q.push(temp->left) ;
26                 if (temp->right != NULL)
27                     q.push(temp->right) ;
28                 level.push_back(temp->val) ;
29             }
30             res.push_back(level) ;
31             level.clear() ;
32         }
33         return res;
34     }
35 };

 

 

102. Binary Tree Level Order Traversal

原文:https://www.cnblogs.com/mengchunchen/p/10262630.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!