Advent of Code 2024 day 11

aoc11

#!/usr/bin/env raku
use v6.d;
$*OUT.out-buffer = False;   # Autoflush

# Advent of Code 2024 day 11 -- https://adventofcode.com/2024/day/11

sub split-in-half($n) { $n.comb(/\w ** { $n.chars div 2 }/)».Int }

use experimental :cached;
multi blink($stone, $times) is cached
{
    return 1 if $times == 0;

    my @new-stones = do given $stone {
        when 0 { 1 }
        when .chars %% 2 { split-in-half($_) }
        default { $_ × 2024 }
    }

    return blink(@new-stones, $times-1).sum;
}

multi blink(@stones, $times) { @stones».&blink($times).sum }

sub MAIN(IO() $inputfile where *.f = 'aoc11.input')
{
    my @stones = $inputfile.words».Int;
    say "Part 1: ", blink(@stones, 25);
    say "Part 2: ", blink(@stones, 75);
}