最長共通部分列問題

Program.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;

namespace ProgrammingContestChallenge.LongestCommonSubsequence
{
    class CharInfo
    {
        public char Char { get; set; }
        public int[] Indexes { get; set; }
    }

    static class Program
    {
        private const string A = "XMJYAUZ";
        private const string B = "MZJAWXU";

        static void Main(string[] args)
        {
            string s = A;
            if (A.Length > B.Length)
            {
                s = B;
            }
            string l = s == A ? B : A;

            int d = 0;
            var t = s
                .Select(c => new CharInfo
                    {
                        Char = c,
                        Indexes = l.Select((x, i) => new { Char = x, Index = i }).Where(x => x.Char == c)
                                   .Select(x => x.Index).ToArray()
                    })
                .ToArray()
                .Recursive(
                    (sequence, f) =>
                        {
                            int index = 0;
                            d++;
                            return sequence.Any() ? new[]
                                {
                                    ((Func<IEnumerable<CharInfo>, Delegate, IEnumerable<char>>)f)(sequence.Skip(1).ToArray(), f),
                                    sequence.Where(c => c.Indexes.Any(x => x >= index) && (index = c.Indexes.First(x => x >= index) + 1) != -1).Select(x => x.Char).ToArray()
                                }.OrderByDescending(x => x.Count()).First().ToArray() : Enumerable.Empty<char>();
                        }
                );
            string result = new string(t.ToArray());
            Console.WriteLine("Count: " + result.Length.ToString());
            Console.WriteLine(result);
        }

        public static IEnumerable<TResult> Recursive<T, TResult>(this IEnumerable<T> source, Func<IEnumerable<T>, Delegate, IEnumerable<TResult>> func)
        {
            return func(source, func);
        }
    }
}