我有輸入就像“dir1/dir2/Demo.txt”結合我想要的輸出“dir1/dir2/Demo.txt”“dir1/dir2/DEMO.txt”"dir1/DIR2/Demo.txt"“dir1/DIR2/DEMO.txt”"DIR1/dir2/Demo.txt""DIR1/dir2/DEMO.txt"“DIR1/DIR2/Demo.txt”"DIR1/DIR2/DEMO.txt"據我所知，我編寫的代碼如下  var s = "dir1/dir2/Demo.txt";   List<string> listPermutations = new List<string>();   string[] array = s.Split('/');   int iterations = (1 << array.Length) -1;   for( int i = 0; i <= iterations; i++ )   {       for( int j = 0; j < array.Length; j++ )            array[j] = (i & (1<<j)) != 0                ? array[j].ToUpper()                : array[j];       listPermutations.Add(string.Join("/",array ));   }