use strict;
use warnings;
use Benchmark qw/ cmpthese /;;

for my $count ( 100, 1_000, 10_000, 100_000 ) {
    cmpthese( -5, {
        1 => sub {
            my @a = map { log } 2 .. $count;
            my %h;
            keys %h = @a;
            $h{ $_ } = log for @a;
            return \%h
        },
        2 => sub {
            my @a = map { log } 2 .. $count;
            my %h;
            $h{ $_ } = log for @a;
            return \%h
        },
        3 => sub {
            my @a = map { log } 2 .. $count;
            my %h;
            keys %h = @a;
            @h{ @a } = map { log } @a;
            return \%h
        },
        4 => sub {
            my @a = map { log } 2 .. $count;
            my %h;
            @h{ @a } = map { log } @a;
            return \%h
        },
    })
}