Binray Search C#_Samson

using System;
using System.Linq;
using System.Collections.Generic;

public class Node
{
    public int Data;
    public Node Left;
    public Node Right;

    public Node(int data)
    {
        Data = data;
        Left = null;
        Right = null;
    }
}

public class BinarySearchTreeChecker
{
    private const long INT_MIN_LONG = long.MinValue;
    private const long INT_MAX_LONG = long.MaxValue;

    public static bool IsBinarySearchTree(Node root)
    {
        return IsBSTUtil(root, INT_MIN_LONG, INT_MAX_LONG);
    }

    private static bool IsBSTUtil(Node node, long min_val, long max_val)
    {
        if (node == null)
        {
            return true;
        }

        if (node.Data < min_val || node.Data > max_val)
        {
            return false;
        }

        bool isLeftValid = IsBSTUtil(node.Left, min_val, (long)node.Data - 1);
        if (!isLeftValid)
        {
            return false;
        }

        bool isRightValid = IsBSTUtil(node.Right, (long)node.Data, max_val);

        return isRightValid;
    }
}

public class Program
{
    public static void Main()
    {
        Console.WriteLine("--- Binary Search Tree Checker ---");
        Console.WriteLine("Enter the data for the 7 nodes separated by spaces:");

        Console.Write("Enter 7 numbers: ");
        string inputLine = Console.ReadLine();

        int[] elements;
        try
        {
            elements = inputLine.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
                                .Select(s => int.Parse(s.Trim()))
                                .ToArray();
        }
        catch (FormatException)
        {
            Console.WriteLine("\nInvalid input. Please ensure all entries are integers separated by spaces. Exiting.");
            return;
        }

        if (elements.Length != 7)
        {
            Console.WriteLine($"\nInput error: Expected 7 numbers but received {elements.Length}. Exiting.");
            return;
        }

        Node root = new Node(elements[0]);

        root.Left = new Node(elements[1]);

        root.Right = new Node(elements[2]);

        root.Left.Left = new Node(elements[3]);

        root.Left.Right = new Node(elements[4]);

        root.Right.Left = new Node(elements[5]);

        root.Right.Right = new Node(elements[6]);

        Console.WriteLine("\n--- Tree Construction Complete. Checking structure... ---");

        bool is_bst = BinarySearchTreeChecker.IsBinarySearchTree(root);

        Console.Write("\nThe inputted data elements are structured as a: ");
        if (is_bst)
        {
            Console.WriteLine("BINARY SEARCH TREE (BST).");
        }
        else
        {
            Console.WriteLine("NOT a Binary Search Tree (BST).");
        }
    }
}