using System;

using System.Numerics;

using System.Text;

​

namespace AnagramCalculator

{

    public class Program

    {

        public static void Main(string[] args)

        {

            while (true)

            {

                //Frequency of characters, want to re-gen or clear every run

                byte[] charFrequency = new byte[26];

                uint charactersUsed = 0;

​

                //Get user input

                var entry = Console.ReadLine();

​

                //For each character entered, increment it's position in the frequency array

                foreach (var character in entry.ToLower())

                {

                    if(character >= 97 && character <= 122)

                    {

                        //ASCII a = 97; this will be position zero in the array

                        charFrequency[character - 97]++;

                        //since there's a chance we don't use the character, increment this value to show we did

                        charactersUsed++;

                    }

                }

​

                //Using biginteger for very large numbers

                BigInteger numerator = Factorial(charactersUsed);

                BigInteger denominator = 1;

​

                //Multiply the denominator by all characters frequency factorials

                foreach (var item in charFrequency)

                {

                    denominator *= Factorial(item);

                }

​

                //Display our output

                Console.WriteLine("Anagram possibilities: " + (numerator / denominator).ToString());

                Console.WriteLine("Numerator: " + numerator.ToString());

                Console.WriteLine("Denominator: " + denominator.ToString());

​

                for (int i = 0; i < 26; i++)

                {

                    Console.WriteLine(((char)(i+97)).ToString() + ": " + charFrequency[i]);

                }

            }

​

        }

​

        static BigInteger Factorial(BigInteger n)

        {

            BigInteger res = 1;

            while (n > 1)

            {

                res *= n;

                n -= 1;

            }

            return res;

        }

    }

​

​

}

​