#! perl -slw
use strict;
use List::Util qw[ shuffle ];

our $MAX	||= 20;
our $N 		= defined $N ? $N : 5;

my @values = shuffle( 1 .. $MAX );
my @top = topNbsAB_p( $N, sub { $_[ 0 ] <=> $_[ 1 ] }, \@values );
print join(" ", @top);

   @top = topNbsAB_p( $N, sub { $_[ 1 ] <=> $_[ 0 ] }, \@values );
print join(" ", @top);

  @values = shuffle( 'A' .. 'Z' );
  @top = topNbsAB_p( $N, sub { $_[ 0 ] cmp $_[ 1 ] }, \@values );
print join(" ", @top);

   @top = topNbsAB_p( $N, sub { $_[ 1 ] cmp $_[ 0 ] }, \@values );
print join(" ", @top);

sub topNbsAB_p {
	my( $n, $CMP, $data )  = @_;    
	return unless $n > 0;
	my @ST;
	my $selected = 0;

	for my $val ( @$data ) {  
		$ST[ $selected++ ] = $val if $selected < $n;
		next if( $CMP->( $val, $ST[ $selected-1 ] ) < 0 );     

		my $left = 0;                                                   
		my $right = ($selected >1) ? $selected -1 : $selected;
		while( $left < $right ) {                                      
			my $middle = ( $left + $right ) >> 1;                      
			if( $CMP->( $val, $ST[ $middle ] ) <= 0 ) {      
				$left = $middle + 1;                                    
			} else {                                                 
				$right = $middle;                                       
			}                                                        
		} 
		for( my $k = $selected; $k >= $left; $k-- ) { $ST[ $k ] = $ST[ $k - 1 ] };     
		$ST[ $left ] = $val;                                           
	}
	return @ST[ 0 .. $selected-1 ];                                 
}                                                 

__END__
P:\test>junk3 -MAX=10 -N=0





P:\test>junk3 -MAX=10 -N=1
10
1
Z
A

P:\test>junk3 -MAX=10 -N=2
10 9
1 2
Z Y
A B

P:\test>junk3 -MAX=10 -N=10
10 9 8 7 6 5 4 3 2 1
1 2 3 4 5 6 7 8 9 10
Z Y X W V U T S R Q
A B C D E F G H I J

P:\test>junk3 -MAX=10 -N=11
10 9 8 7 6 5 4 3 2 1
1 2 3 4 5 6 7 8 9 10
Z Y X W V U T S R Q P
A B C D E F G H I J K

P:\test>junk3 -MAX=10 -N=26
10 9 8 7 6 5 4 3 2 1
1 2 3 4 5 6 7 8 9 10
Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

P:\test>junk3 -MAX=10 -N=27
10 9 8 7 6 5 4 3 2 1
1 2 3 4 5 6 7 8 9 10
Z Y X W V U T S R Q P O N M L K J I H G F E D C B A
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z