Re^2: random pairs

[Perlbotics]

Unfortunately, that algorithm does not avoid unwanted pairs like [1,23] and [23,1].

Here is a naive try until it works approach:

use strict;
use warnings;
use List::Util qw(shuffle);

my (%keys, @rnds, @pairs);

do {
  %keys  = ();
  @rnds  = shuffle (0..99);
  @pairs = map{ my $r = $rnds[$_];
                $keys{"$_,$r"}++;
                $keys{"$r,$_"}++;
                [ $_, $r ]
          } (0..99);
} while ( scalar keys %keys != 200 ); # no symmetry means 200 distinct
+ pairs

# @pairs = shuffle( @pairs ); # uncomment if wanted

printf( "%3d %3d\n", @{$pairs[$_]}) for (0..99);