use Benchmark 'cmpthese';

my $no_total = 1_000_000;#number of points

my $d = 1000;

sub gen_xy { ( int(rand($d)),int(rand($d)) ); }

sub in_circle {
    my ($x,$y) = @_;
    ($x - $d/2)**2 + ($y - $d/2)**2 <= ($d/2)**2
        ? 1
        : 0;
}

my $subs = {
    powers => sub {
        my $no_in;
        $no_in += rand()**2 + rand()**2 <= 1
            for 1 .. $no_total;
        return $no_in/$no_total * 4;
    },
    multiply => sub {
        my $no_in;
        my ( $x, $y );
        for ( 1 .. $no_total ) {
            ( $x, $y ) = ( rand, rand );
            $no_in += $x*$x + $y*$y <= 1;
        }
        return $no_in/$no_total * 4;
    },
    original => sub {
        my $d = 1000;#diameter
        my $no_in=0;

        $no_in += in_circle gen_xy
            for 1..$no_total;
        return $no_in/$no_total * 4;
    },
};


print "$_: ", $subs->{$_}->(), "\n"
    for keys %$subs;

cmpthese( 5, $subs );
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