LeftViewOfTree.cpp

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

// Node structure for the binary tree
struct Node {
    int data;
    Node* left;
    Node* right;
    // Constructor to initialize
    // the node with a value
    Node(int val) : data(val), left(nullptr), right(nullptr) {}
};

class Solution {
public:
    // Function to return the Right view of the binary tree
    vector<int> rightsideView(Node* root){
        // Vector to store the result
        vector<int> res;
        
        // Call the recursive function
        // to populate the right-side view
        recursionRight(root, 0, res);
        
        return res;
    }
    
    // Function to return the Left view of the binary tree
    vector<int> leftsideView(Node* root){
        // Vector to store the result
        vector<int> res;
        
        // Call the recursive function
        // to populate the left-side view
        recursionLeft(root, 0, res);
        
        return res;
    }

private:
    // Recursive function to traverse the
    // binary tree and populate the left-side view
    void recursionLeft(Node* root, int level, vector<int>& res){
        // Check if the current node is NULL
        if(root == NULL){
            return;
        }
        
        // Check if the size of the result vector
        // is equal to the current level
        if(res.size() == level){
            // If equal, add the value of the
            // current node to the result vector
            res.push_back(root->data);
        }
        
        // Recursively call the function for the
        // left child with an increased level
        recursionLeft(root->left, level + 1, res);
        
        // Recursively call the function for the
        // right child with an increased level
        recursionLeft(root->right, level + 1, res);
    }
    
    // Recursive function to traverse the
    // binary tree and populate the right-side view
    void recursionRight(Node* root, int level, vector<int> &res){
        // Check if the current node is NULL
        if(root == NULL){
            return;
        }
        
        // Check if the size of the result vector
        // is equal to the current level
        if(res.size() == level){
            // If equal, add the value of the
            // current node to the result vector
            res.push_back(root->data);
            
            // Recursively call the function for the
            // right child with an increased level
            recursionRight(root->right, level + 1, res);
            
            // Recursively call the function for the
            // left child with an increased level
            recursionRight(root->left, level + 1, res);
        }
    }
};



int main() {
    // Creating a sample binary tree
    Node* root = new Node(1);
    root->left = new Node(2);
    root->left->left = new Node(4);
    root->left->right = new Node(10);
    root->left->left->right = new Node(5);
    root->left->left->right->right = new Node(6);
    root->right = new Node(3);
    root->right->right = new Node(10);
    root->right->left = new Node(9);

    Solution solution;

        // Get the Right View traversal
    vector<int> rightView = solution.rightsideView(root);

    // Print the result for Right View
    cout << "Right View Traversal: ";
    for(auto node: rightView){
        cout << node << " ";
    }
    cout << endl;

    // Get the Left View traversal
    vector<int> leftView = solution.leftsideView(root);

    // Print the result for Left View
    cout << "Left View Traversal: ";
    for(auto node: leftView){
        cout << node << " ";
    }
    cout << endl;

    return 0;
}