using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.RegularExpressions;

​

internal static class Program

{

    /// <summary>

    /// </summary>

    public static Dictionary<int, bool> PrimeCache = new Dictionary<int, bool>();

​

    private static void Main(string[] args)

    {

        var result = GetInput()

            .TransformInputToArray()

            .TransformTo2Darray()

            .ResetAllPrimeNumbers()

            .WalkThroughTheNode();

​

        Console.WriteLine($"The Maximum Total Sum Of Non-Prime Numbers From Top To Bottom Is:  {result}");

        Console.ReadKey();

    }

​

    /// <summary>

    ///     Prepare input

    /// </summary>

    /// <returns></returns>

    private static string GetInput()

    {

        const string input = @"//triangle values. "

        return input;

    }

​

    /// <summary>

    ///     Transform the input to array

    /// </summary>

    /// <param name="input"></param>

    /// <returns></returns>

    private static string[] TransformInputToArray(this string input)

    {

        return input.Split(new[] {Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries);

    }

​

    /// <summary>

    ///     Transform the array to 2D array

    /// </summary>

    /// <param name="arrayOfRowsByNewlines"></param>

    /// <returns></returns>

    private static int[,] TransformTo2Darray(this string[] arrayOfRowsByNewlines)

    {

        var tableHolder = new int[arrayOfRowsByNewlines.Length, arrayOfRowsByNewlines.Length + 1];

​

        for (var row = 0; row < arrayOfRowsByNewlines.Length; row++)

        {

            var eachCharactersInRow = arrayOfRowsByNewlines[row].ExtractNumber();

​

            for (var column = 0; column < eachCharactersInRow.Length; column++)

                tableHolder[row, column] = eachCharactersInRow[column];

        }

        return tableHolder;

    }

​

    /// <summary>

    ///     Extract Number from the row

    /// </summary>

    /// <param name="rows"></param>

    /// <returns></returns>

    private static int[] ExtractNumber(this string rows)

    {

        return

            Regex

                .Matches(rows, "[0-9]+")

                .Cast<Match>()

                .Select(m => int.Parse(m.Value)).ToArray();

    }

​

    /// <summary>

    ///     Reset all the prime number to zero

    /// </summary>

    /// <param name="tableHolder"></param>

    /// <returns></returns>

    private static int[,] ResetAllPrimeNumbers(this int[,] tableHolder)

    {

        var length = tableHolder.GetLength(0);

        for (var i = 0; i < length; i++)

        {

            for (var j = 0; j < length; j++)

            {

                if (tableHolder[i, j] == 0) continue;

                if (IsPrime(tableHolder[i, j]))

                    tableHolder[i, j] = 0;

            }

        }

        return tableHolder;

    }

​

    /// <summary>

    ///     Walk through all the non prime

    /// </summary>

    /// <param name="tableHolder"></param>

    /// <returns></returns>

    private static int WalkThroughTheNode(this int[,] tableHolder)

    {

        var tempresult = tableHolder;

        var length = tableHolder.GetLength(0);

​

        // walking through the non-prime node

​

        for (var i = length - 2; i >= 0; i--)

        {

            for (var j = 0; j < length; j++)

            {

                var c = tempresult[i, j];

                var a = tempresult[i + 1, j];

                var b = tempresult[i + 1, j + 1];

                if ((!IsPrime(c) && !IsPrime(a)) || (!IsPrime(c) && !IsPrime(b)))

                    tableHolder[i, j] = c + Math.Max(a, b);

            }

        }

        return tableHolder[0, 0];

    }

​

    /// <summary>

    ///     prime number check

    /// </summary>

    /// <param name="number"></param>

    /// <returns></returns>

    public static bool IsPrime(this int number)

    {

        // Test whether the parameter is a prime number.

        if (PrimeCache.ContainsKey(number))

        {

            bool value;

            PrimeCache.TryGetValue(number, out value);

            return value;

        }

        if ((number & 1) == 0)

        {

            if (number == 2)

            {

                if (!PrimeCache.ContainsKey(number)) PrimeCache.Add(number, true);

                return true;

            }

            if (!PrimeCache.ContainsKey(number)) PrimeCache.Add(number, false);

            return false;

        }

​

        for (var i = 3; i*i <= number; i += 2)

        {

            if (number%i == 0)

            {

                if (!PrimeCache.ContainsKey(number)) PrimeCache.Add(number, false);

                return false;

            }

        }

        var check = number != 1;

        if (!PrimeCache.ContainsKey(number)) PrimeCache.Add(number, check);

        return check;

    }

}

​