(C #) the second question of ACM

This is a bit difficult. The second requirement is not met. For the BBC. There will be duplicates.
BBC
BCB
BCB
CBB
Although filtering is not repeated, it is certainly not the original intention of the question. You have time to redo it.

Using System;
Using System. Collections. Generic;
Using System. text;
Using System. IO;

Namespace Acm2
{
Class Program
{
Static   Void Main ( String [] ARGs)
{
Filestream FS =   New Filestream (ARGs [ 0 ], Filemode. Open, fileaccess. Read );
Streamreader SR =   New Streamreader (FS );
String S = Sr. Readline ();
Int N =   Int . Parse (s );
For ( Int I =   0 ; I < N; I ++ )
{
S = Sr. Readline ();
Console. writeline ( " Case "   + (I +   1 ));
Deal (s );

}
}
Static   String Sort ( String Str)
{
Char [] CS = Str. tochararray (); Char Temp;
For ( Int I = 0 ; I < CS. length; I ++ )
For ( Int J = I; j < CS. length; j ++ )
If (CS [I] > CS [J])
{< br> temp = CS [I];
CS [I] = CS [J];
CS [J] = temp;
}
Return   New   String (CS );
}
Static   Void Deal ( String Str)
{
String Mstr = Sort (STR );
String [] STRs = Dealf (mstr );
For ( Int I =   0 ; I < STRs. length; I ++ )
Console. writeline (STRs [I]);
}
Static   String [] Dealf ( String Str)
{
If (Str. Length =   1 )
Return   New   String [] {STR} ;
If (Str. Length =   2 )
{
String [] Torets =   New   String [ 2 ];
Torets [ 0 ] = STR;
Torets [ 1 ] = Str. substring ( 1 ) + Str. substring ( 0 , 1 );
Return Torets;
}
String C = Str. substring ( 0 , 1 );
String [] RET = Dealf (Str. substring ( 1 ));
String [] Toret =   New   String [Ret. Length * 2 ];
For ( Int I =   0 ; I < Toret. length; I ++ )
{
If (I < Toret. Length /   2 )
Toret [I] = C + RET [I];
Else
Toret [I] = RET [I - Ret. Length] + C;
}
Return Toret;
}
}
}