[leetcode] 199. Binary Tree Right Side View

Binary Tree Right Side View

描述

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,



You should return [1, 3, 4]

我的代码

可以广搜也可以深搜：

深搜代码：

/**
* 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> rlt;
dfs(root, 1, rlt);
return rlt;
}
private:
void dfs(TreeNode* root, int step, vector<int>& vec)
{
if (!root) return;
if (vec.size()<step) vec.push_back(root->val);
dfs(root->right, step+1, vec);
dfs(root->left, step+1, vec);
}
};

广搜代码：

*/
class Solution {
public:
vector<int> rightSideView(TreeNode* root) {
queue<TreeNode*> q;
vector<int> rlt;
if (root)
{
q.push(root);
while(!q.empty())
{
rlt.push_back(q.front()->val);
int _size=q.size();
while(_size)
{
TreeNode* tmp=q.front();
q.pop();
if (tmp->right) q.push(tmp->right);
if (tmp->left) q.push(tmp->left);
_size--;
}
}
}
return rlt;
}
};