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.
Example:
Input: [1,2,3,null,5,null,4]
Output: [1, 3, 4]
Explanation: 1 <---
/ \
2 3 <---
\ \
5 4 <---
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水。。。。。。用bfs就可以快速先解决掉了 C++代码：
/**
* 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:
vector<int> rightSideView(TreeNode* root) {
vector<int> vec;
if(!root) return vec;
queue<TreeNode*> q;
q.push(root);
while(!q.empty()){
for(int i = q.size(); i > ; i--){
auto t = q.front();
q.pop();
if(i == ){
vec.push_back(t->val);
}
if(t->left) q.push(t->left);
if(t->right) q.push(t->right);
}
}
return vec;
}
};