using System;

using System.Collections.Generic;

​

public class Chesspiece

{

    public int movedistance;

    public string name;

    public int[,] moveformat;

}

​

public class Program

{

    public  static int VariantCount = 0;

    public static void Main()

    {

        var myChessPiece = new Chesspiece();

        myChessPiece.movedistance = 3;

        myChessPiece.name = "Knight";

        myChessPiece.moveformat = new int[2, 1];

        List<string> listofNumbers = new List<string>();

        int[,] dialPad = new int[4, 3] { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 }, { 11, 0, 12 } };

        for (int yaxis = 0; yaxis < 3; yaxis++) // I didn't include the 4th row as a valid row as it only has #,0,*

        {

            // move through all keys except 0  + 1

            for (int xaxis = 0; xaxis < 3; xaxis++)

            {

                // Skip numbers starting with 1

                if (yaxis == 0 && xaxis == 0)

                {

                    yaxis = 1;

                }

                int firstPos = xaxis;

                int secondPos = yaxis;

                /// I am enforcing  seven digits by limiting length

                for (int phoneNumberCounter = 0; phoneNumberCounter < 6; phoneNumberCounter++)

                {

                    if (phoneNumberCounter > 0) // dont move on first , not sure if that was a requirement

                    {

                        // LIMITATION1: IT DOESNT GO THROUGH THE VARIANTS OF EACH VARIANT, this is a linear calculation, only vetting the possible different  positions on each step

                        // LIMITATION2: it doesn't consider  duplicate numbers,  in order to do this you have to store the numbers ; my first attempt was going to do this but I ran out of time

                        Try8KnightMoves(ref firstPos, ref secondPos);

                    }

                }

​

            }

        }

​

        Console.WriteLine("Number of viable numbers for {0} is {1}", myChessPiece.name, VariantCount);

​

    }

    // in consider how all the other chess pieces move, they rest can have a more lineal flow but it seems that the knight requires a specific function to determine movement type. 

    // all other pieces moves linearly and could be more easily defined in a commonet chess piece move like above

    // Knights are unique they have  8 possible moves

    public static void Try8KnightMoves(ref int firstPos, ref int secondPos)

    {

        //int[] moveX = {2, 1, -1, -2, -2, -1, 1, 2}; -- originally I thought there was 8 total moves but 1,2 = 2,1 and etc. I think there is only 4

        //int[] moveY = { 1, 2, 2, 1, -1, -2, -2, -1 };

        int[] moveX = {2, -2, -2, 2};

        int[] moveY = { 1, 1, -1, -1 };

​

        for (int j = 0; j < moveX.Length; j++)

        {

            // if move is valid, increase variantcount

            if (KnightMovementOpt(ref firstPos, ref secondPos, moveX[j], moveY[j]))  { VariantCount += 1; }

        }

​

    }

    public static bool KnightMovementOpt(ref int firstPos, ref int secondPos, int move1, int move2)

    {

        int possibleFirstPos = -1;

        int possibleSecondPos = -1;

        // Make sure its within bounds

        if (firstPos + move1 < 4 && firstPos + move1 >= 0)

        {

            possibleFirstPos += 2;

            if (secondPos + move2 <= 2 && secondPos + move2 >= 0)

            {

                possibleSecondPos = secondPos + 1;

            }

        }

        // Make sure we didn't hit the pound or asterisk

​

        if ( possibleFirstPos != -1 && (possibleFirstPos != 1 || possibleFirstPos != 2)  && possibleSecondPos != 3)

        {

            firstPos = possibleFirstPos;

            secondPos = possibleSecondPos;

            return true;

        }

        else

        {

            return false;

        }

​

    }

​

​

}