有关字符串输出的问题

Question

大神们，如何在确认了一个字符串比如“abcde”,如何用代码实现输出“a;b;c;d;e;ab;ac;ad;ae.......”
从一个到5个字符所有的排列组合，而且每一个组合里面还不能有重复的字符，

Answer 1

 using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            string metachars = "abcde";

            for (int i = 1; i <= metachars.Length; i++)

            {

                foreach (string s in foo(metachars, i))

                {

                    Console.WriteLine(s);

                }

            }

        }



        static IEnumerable<string> foo(string metachars, int i)

        {

            var query = metachars.Select(x => x.ToString().AsEnumerable());

            while (query.First().Count() < i)

                query = query.SelectMany(x => metachars.Where(y => y > x.Last()).Select(y => x.Concat(y.ToString().AsEnumerable())));

            return query.Select(x => string.Join(",", x));

        }

    }

}