Data commit

Task/Permutations/Batch-File/permutations.bat

@@ -0,0 +1,33 @@
+@echo off
+setlocal enabledelayedexpansion
+set arr=ABCD
+set /a n=4
+:: echo !arr!
+call :permu  %n% arr
+goto:eof
+
+:permu num  &arr
+setlocal
+if %1 equ 1 call echo(!%2! & exit /b
+set /a "num=%1-1,n2=num-1"
+set arr=!%2!
+for /L %%c in (0,1,!n2!) do (
+   call:permu !num! arr
+   set /a  n1="num&1"
+   if !n1! equ 0 (call:swapit !num! 0 arr) else (call:swapit !num! %%c arr)
+   )
+   call:permu !num! arr
+endlocal & set %2=%arr%
+exit /b
+
+:swapit  from  to  &arr
+setlocal
+set arr=!%3!
+set temp1=!arr:~%~1,1!
+set temp2=!arr:~%~2,1!
+set arr=!arr:%temp1%=@!
+set arr=!arr:%temp2%=%temp1%!
+set arr=!arr:@=%temp2%!
+:: echo %1 %2 !%~3! !arr!
+endlocal & set %3=%arr%
+exit /b