C#尋找字串的所有排列組合

C#尋找字串的所有排列組合

// 1. remove first char// 2. find permutations of the rest of chars// 3. Attach the first char to each of those permutations.//     3.1  for each permutation, move firstChar in all indexes to produce even more permutations.// 4. Return list of possible permutations.  public string[] FindPermutations(string word)        {            if (word.Length == 2)            {                char[] _c = word.ToCharArray();                string s = new string(new char[] { _c[1], _c[0] });                return new string[]                {                    word,                    s                };            }              List _result = new List();              string[] _subsetPermutations = FindPermutations(word.Substring(1));            char _firstChar = word[0];            foreach (string s in _subsetPermutations)            {                string _temp = _firstChar.ToString() + s;                _result.Add(_temp);                char[] _chars = _temp.ToCharArray();                for (int i = 0; i < _temp.Length - 1; i++)                {                    char t = _chars[i];                    _chars[i] = _chars[i + 1];                    _chars[i + 1] = t;                    string s2 = new string(_chars);                    _result.Add(s2);                }            }            return _result.ToArray();        }

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