Implement right side view of binary tree

[Subhosjx]

PR Title Format: Problem no.Problem name.cpp

Intuition

When viewing a binary tree from the right side, only the rightmost node at each depth is visible. That means for every level of the tree, we need to capture the last node in that level’s traversal.

Approach

We can solve this with BFS (level order traversal):

1. Use a queue to traverse the tree level by level.
2. At each level, iterate through all nodes.
3. The last node in the level (rightmost one) is added to the result.
4. Push children (left, then right) to continue traversal.

Code Solution (C++)

    // Your code goes here
    class Solution {
public:
    vector<int> rightSideView(TreeNode* root) {
        // unordered_map<int,int>map;
        vector<int>ans;
        int level=-1;
        traverseRightSide(root,level,0,ans);
        return ans;
    }
    void traverseRightSide(TreeNode* root,int &mainLevel,int level, vector<int>&ans){
        if(root==NULL) return ;

        if(mainLevel<level){
            ans.push_back(root->val);
            mainLevel=max(mainLevel,level);
        }

        traverseRightSide(root->right,mainLevel,level+1,ans);
        traverseRightSide(root->left,mainLevel,level+1,ans);
    }
};

Related Issues

By submitting this PR, I confirm that:

• This is my original work not totally AI generated
• I have tested the solution thoroughly on leetcode
• I have maintained proper PR description format
• This is a meaningful contribution, not spam

Summary by Sourcery

New Features:

• Add DFS-based solution for computing the right side view of a binary tree using level tracking

[sourcery-ai]

Reviewer's Guide

This PR adds a DFS-based recursive solution for the right side view of a binary tree, using a helper function that traverses the right subtree before the left while tracking depth to capture the first node seen at each level.

Sequence diagram for rightSideView traversal (DFS right-first)

sequenceDiagram
participant "Caller"
participant Solution
participant "TreeNode (root)"
Caller->>Solution: rightSideView(root)
Solution->>Solution: traverseRightSide(root, mainLevel, 0, ans)
alt root is not NULL
  Solution->>Solution: traverseRightSide(root->right, mainLevel, level+1, ans)
  Solution->>Solution: traverseRightSide(root->left, mainLevel, level+1, ans)
end
Solution-->>Caller: return ans

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Class diagram for Solution and TreeNode classes (right side view implementation)

classDiagram
class TreeNode {
  int val
  TreeNode* left
  TreeNode* right
  TreeNode()
  TreeNode(int x)
  TreeNode(int x, TreeNode* left, TreeNode* right)
}
class Solution {
  vector<int> rightSideView(TreeNode* root)
  void traverseRightSide(TreeNode* root, int &mainLevel, int level, vector<int>& ans)
}
TreeNode <|-- Solution: uses

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File-Level Changes

Change	Details	Files
Implement recursive right-side view traversal	Added rightSideView public method Introduced traverseRightSide helper function Removed unused BFS/queue code placeholder	199. Binary Tree Right Side View.cpp
Process right subtree before left to capture rightmost nodes	Order recursive calls: right child first, then left Ensure first node at each depth is recorded	199. Binary Tree Right Side View.cpp
Track and update depth to identify new levels	Added level and mainLevel parameters Conditional push to ans when mainLevel<level Update mainLevel with max(level, mainLevel)	199. Binary Tree Right Side View.cpp

Possibly linked issues

• Add: LeetCode #121 - Best Time to Buy and Sell Stock solution #199: The PR provides a DFS solution for the Binary Tree Right Side View problem, which is the same problem as the issue.

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[sourcery-ai]

Hey there - I've reviewed your changes - here's some feedback:

• Your PR description describes a BFS approach but you actually implemented a DFS solution – update the description to match your chosen strategy for clarity.
• Remove the unused commented‐out unordered_map and consider renaming ‘mainLevel’ to something like ‘maxDepth’ or ‘currentMaxLevel’ for better readability.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Your PR description describes a BFS approach but you actually implemented a DFS solution – update the description to match your chosen strategy for clarity.
- Remove the unused commented‐out unordered_map and consider renaming ‘mainLevel’ to something like ‘maxDepth’ or ‘currentMaxLevel’ for better readability.

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[github-actions]

🎉 Congrats on getting your PR merged in, @Subhosjx! 🙌🏼

Thanks for your contribution every effort helps improve the project.

Looking forward to seeing more from you! 🥳✨