AoC 2022, day 13

use MONKEY-SEE-NO-EVAL;

multi compare(UInt:D \a, UInt:D \b) { a <=> b }
multi compare(UInt:D \a, @B)        { compare([a], @B) }
multi compare(@A, UInt:D \b)        { compare(@A, [b]) }

multi compare(@A, @B --> Order:D)   {
    return +@B == 0 ?? Order::Same !! Order::Less if +@A == 0;
    return Order::More if +@B == 0;
    compare(@A[0], @B[0]) or compare(@A.tail(*-1), @B.tail(*-1))
}

my @p1 = $*IN.split("\n\n").map({ .lines.map({ EVAL(.subst(/']' <?before ']'>/, '],', :g)) }).Array });
put 'part 1: ', (^+@p1).map(-> \n { n + 1 if compare(|@p1[n]) == Order::Less }).sum;

my @p2 = (|@p1[*;*], [[2],], [[6],]).sort({ compare($^a, $^b) });
put 'part 2: ', (@p2.first(* eqv [[2],], :k) + 1) * (@p2.first(* eqv [[6],], :k) + 1);