C# 字符串排序组合

1.string s1="abc";string s2="aabbcd";都已按照字母排序,现需要组合两个字符串得到 string s3="aaabbbccd";按照字母排序。

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

namespace ConsoleApplication3{    class Program    {        static void Main(string[] args)        {            string s1 = "abc";             string s2 = "aabbcd";            List<char> list = (s1 + s2).ToList<char>();            list.Sort();            Console.Write(new string(list.ToArray()));            Console.ReadKey();

        }    }}