Binary Search Tree.cpp

#include <bits/stdc++.h>
using namespace std;

// 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> result;
        if (!root) return result;

        queue<TreeNode*> q;
        q.push(root);

        while (!q.empty()) {
            int size = q.size();
            for (int i = 0; i < size; i++) {
                TreeNode* node = q.front();
                q.pop();

                // Add the last node of each level
                if (i == size - 1)
                    result.push_back(node->val);

                if (node->left)
                    q.push(node->left);
                if (node->right)
                    q.push(node->right);
            }
        }

        return result;
    }
};

// Example usage
int main() {
    /*
        Example Tree:
              1
             / \
            2   3
             \   \
              5   4
        Expected output: 1 3 4
    */

    TreeNode* root = new TreeNode(1);
    root->left = new TreeNode(2);
    root->right = new TreeNode(3);
    root->left->right = new TreeNode(5);
    root->right->right = new TreeNode(4);

    Solution sol;
    vector<int> ans = sol.rightSideView(root);

    for (int x : ans) cout << x << " ";
    cout << endl;

    return 0;
}