LeetCode-Problems/Medium Problems/199_Binary_Tree_Right_Side_View.cpp at main · UdaySharmaGitHub/LeetCode-Problems · GitHub

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/*
199. Binary Tree Right Side View
Given the root of 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 1:
Input: root = [1,2,3,null,5,null,4]
Output: [1,3,4]
Example 2:
Input: root = [1,null,3]
Output: [1,3]
Example 3:
Input: root = []
Output: []
Constraints:
The number of nodes in the tree is in the range [0, 100].
-100 <= Node.val <= 100
*/
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
private:
void solve(TreeNode* root,vector<int>& a,int lvl){
    if(root==nullptr) return ;

    if(lvl==a.size())  a.push_back(root->val);
    solve(root->right,a,lvl+1);
    solve(root->left,a,lvl+1);
}
public:
    vector<int> rightSideView(TreeNode* root) {
        vector<int> ans;
        solve(root,ans,0);
        return ans;
    }
};