Binary Tree Right Side View

Binary Tree Right Side View

Total Accepted: 28755 Total Submissions: 92186 Difficulty: Medium

 

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].

 (M) Populating Next Right Pointers in Each Node

 

/**
 * 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:
    void dfs(TreeNode* root,vector<int>& res,int& res_size,int depth){
        if(!root) return ;
        if(depth==res_size){
            res_size++;
            res.push_back(root->val);
        }
        dfs(root->right,res,res_size,depth+1);
        dfs(root->left,res,res_size,depth+1);
    }
    vector<int> rightSideView(TreeNode* root) {
        vector<int> res;
        int res_size =0;
        dfs(root,res,res_size,0);
        return res;
    }
};

Next challenges: (M) Populating Next Right Pointers in Each Node