use strict;
use warnings;
use 5.010;

my $max = 1000;
my %wins;

for ( 1 .. $max ) {
  my @parcels = ( 1, 0, 0 );
  $wins{hold}   += splice @parcels, rand @parcels, 1;
  $wins{switch} += $parcels[0];
}

say "$_:\t$wins{$_}" for keys %wins;