#!/usr/bin/perl

use Benchmark qw( cmpthese );

my( $count, $len )= @ARGV;
$count ||= 10;
$len ||= 5000;
my $string= join '+', map {
    join '', map {('a'..'z')[rand(26)]} 0..rand($len)
} 1..$count;

sub subst {
    $string =~ s/\+/-/g;
    $string =~ s/\-/+/g;
    0;
}

sub trans {
    $string =~ tr/\+/-/;
    $string =~ tr/\-/+/;
    0;
}

cmpthese( -3, {
    a_s => \&subst,
    b_s => \&subst,
    a_t => \&trans,
    b_t => \&trans,
} );