use strict;
use warnings;

my $start_time = time;
my $n_strings = 10_000;
my $min_len_strings = 20;
my $max_len_strings = 100;

# Generate strings
my @number2letter = ('a' .. 'b');
my @strings = ();
undef $strings[$n_strings];
foreach my $string (@strings){
    $string = '';
    for (1 .. $min_len_strings + rand($max_len_strings - $min_len_strings)) {
        $string .= $number2letter[int rand @number2letter];
    }
}

# Build comparison matrix
my @matches = ();
undef $matches[$n_strings];
foreach my $match(@matches) {
    $match = [];
    undef $match->[$n_strings];
}

# And compare
for my $i (0 .. $#strings) {
    for my $j (0 .. $#strings) {
        $matches[$i][$j] = $strings[$i] eq $strings[$j] ? 1 : 0;
    }    
}

# And finish
my $tot_matches = 0;
for my $i (0 .. $#strings) {
    for my $j (0 .. $#strings) {
        $tot_matches++ if $matches[$i][$j];
    }    
}
my $time = time - $start_time;
print "I ran for $time seconds, and found $tot_matches matches.";