23BSTLevel-OrderTraversal.cpp

#include <iostream>
#include <cstddef>
#include <queue>
#include <string>
#include <cstdlib>

using namespace std;

class Node {
    public:
        int data;
        Node *left, *right;
        Node(int d)
        : data(d), left(NULL), right(NULL) {}
};

class Solution {
    public:
        Node* insert(Node* root, int data) {
            if (root == NULL)
                return new Node(data);
            else 
            {
                Node* cur;
                if (data <= root->data) {
                    cur = insert(root->left, data);
                    root->left = cur;
                }
                else {
                    cur = insert(root->right, data);
                    root->right = cur;
                }           
            return root;
            }
        }

    void levelOrder(Node* root) {
        queue<Node*> queueNode;
        if (root != NULL) {
            queueNode.push(root);
            while (!queueNode.empty()) {
                Node* current {queueNode.front()};
                cout << current->data << " ";
                queueNode.pop();
                if (current->left != NULL)
                    queueNode.push(current->left);
                if (current->right != NULL)
                    queueNode.push(current->right);
            }
        }
	}
};

int main() {
    Solution myTree;
    Node* root {NULL};
    int T, data;
    cin >> T;
    while (T-- > 0) {
        cin >> data;
        root = myTree.insert(root, data);
    }
    myTree.levelOrder(root);
    return 0;
}