------------------------------------------------- permut.perl6 -----------------------
{
   my Int $num = 2;
   try {
      $num = +@*ARGS[0];
   }
   if $num <= 2 {
      $num = 2;
   }
   my Int $index = 1;
   my Int $old = 1;
   my Int $minfree = 1;
   my Bool @f;
   my Int @c;
   for 0..$num -> $i {
      @c[$i] = -1;
      @f[$i] = True;
   }
   say "init fertig ", $num;

   sub freespot(Int $ind){
      if $ind > 0 {
         @f[$ind] = True;
         if $ind < $minfree {
            $minfree = $ind;
         }
      }
   }

   sub takespot(Int $ind){
      if $ind > 0 {
         @f[$ind] = False;
         if $ind == $minfree {
            for $minfree+1..$num -> $i {
               if @f[$i] == True {
                  $minfree = $i;
                  return;
               }
            }
         }
      }
   }

   my Int $count = 1;
   while $index > 0 {
      my Int $start = @c[$index]+1;
      if $start == 0 {
         $start = $minfree;
      }
      for $start..$num -> $i {
         if (@f[$i] == True) {
            freespot(@c[$index]);
            takespot($i);
            @c[$index] = $i;
            if $index < $num {
               $index++;
            } else {
               freespot($i);
               if $num > 100 {
                  for 1..10 -> $j {
                     print @c[$j]," ";
                  }
                  say "... ";
                  for $num-10..$num -> $j {
                     print @c[$j]," ";
                  }
               } else {
                  for 1..$num -> $j {
                     print @c[$j]," ";
                  }
               }
               say " | ",$count;
               $count++;
            } 
            last;
         }
      }
      if $index == $old {
         freespot(@c[$index]);
         @c[$index] = -1;
         $index--;
      }
      $old = $index;
   }
}