输出一个字符串所有排列。注意有重复字符

C# code as below:

 

  递归写的，因为产生了老多string，效率很慢,除去了重复的字符串
   public static List<string> OutPutString(string str)

        {

            List<string> list = new List<string>();

            if (str.Length == 1)

            {

                list.Add(str);

                return list;

            }

            char[] myCharArray = str.ToCharArray();

            for (int i = 0; i < str.Length; i++)

            {

                string str1 = myCharArray[i].ToString();

                //Use OutPutString(), remove myCharArray[i] from string 

                foreach (string str2 in OutPutString(str.Remove(i,1)))

                {

                    //Remove duplicated string

                    if (!list.Contains(str1 + str2))

                    {

                        list.Add(str1 + str2);

                    }

                }

            }

            return list;

        }