#!/usr/bin/perl

use strict;
use warnings;
use Benchmark qw 'cmpthese';
use List::Util 'reduce';

my  $size  = shift || 10_000;
my  $max_l = shift ||     50;
our @data  = map {"1" x (1 + rand $max_l)} 1 .. $size;

our ($p, $s, $g, $r, $f);

cmpthese -5, {
    plain    => '$p = (sort {length($a) <=> length($b)} @data) [0]',
    ST       => '$s = (map  {$_->[0]}
                       sort {$a->[1] <=> $b->[1]}
                       map  {[$_, length]} @data) [0]',
    GRT      => '$g = (map  {substr $_, 4}
                       sort
                       map  {pack "NA*", length($_), $_} @data) [0]',
    reduce   => '$r = reduce {length($a) < length($b) ? $a : $b} @data',
    for      => '$f = $data[0];
                 for (@data) {$f = $_ if length($_) < length($f)}',
};

die unless $p eq $s && $p eq $g && $p eq $r && $p eq $f;

__END__
         Rate     ST    GRT  plain    for reduce
ST     10.6/s     --   -57%   -66%   -95%   -97%
GRT    24.5/s   132%     --   -22%   -89%   -92%
plain  31.3/s   197%    28%     --   -86%   -90%
for     222/s  2004%   805%   609%     --   -28%
reduce  308/s  2817%  1156%   883%    39%     --