【48】199. Binary Tree Right Side View

199. Binary Tree Right Side View

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  • Total Accepted: 68720
  • Total Submissions: 176072
  • Difficulty: Medium
  • Contributors: Admin

 

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.

For example:
Given the following binary tree,

   1            <---
 /   \
2     3         <---
 \     \
  5     4       <---

 

You should return [1, 3, 4].

 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<int> rightSideView(TreeNode* root) {
13         //层序遍历，每次输出queue.back()即可。
14         vector<int> res;
15         if(!root) return res;
16         queue<TreeNode*> q;
17         q.push(root);
18         //res.push_back(root -> val);
19         while(!q.empty()){
20             res.push_back(q.back() -> val);
21             //TreeNode* tmp = q.front();
22             int size = q.size();
23             //q.pop();
24             //res.push_back(q.back() -> val);
25             //q.pop();
26             for(int i = 0; i < size; i++){
27                 TreeNode* tmp = q.front();//在for循环里pop
28                 q.pop();
29                 if(tmp -> left){
30                     q.push(tmp -> left);
31                 }
32                 if(tmp -> right){
33                     q.push(tmp -> right);
34                 }
35             }
36         }
37         return res;
38     }
39 };

 

 
 
posted @ 2017-02-10 07:22  会咬人的兔子  阅读(144)  评论(0)  编辑  收藏  举报