AoC 2023, day 12
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my %mem;
sub solve(@puzzle is copy, @groups is copy) {
my $key = @puzzle.join ~ @groups.join(',');
return %mem{$key} if %mem{$key}.defined;
return 0 if +@puzzle == 0 and +@groups > 0;
if +@groups == 0 {
return @puzzle.grep('#') ?? 0 !! 1;
} else {
return 0 if @puzzle.all eq '.';
}
my $ans = do given @puzzle[0] {
when '.' { solve(@puzzle.tail(*-1), @groups) }
when '?' { solve(@puzzle.tail(*-1), @groups) + solve(['#', |@puzzle.tail(*-1)], @groups) }
when '#' {
return 0 if @groups[0] > +@puzzle;
if @puzzle[^@groups[0]].all eq <# ?>.any {
return 0 if (@puzzle[@groups[0]] // '') eq '#';
solve(@puzzle[@groups[0]+1..*], @groups.tail(*-1))
}
}
}
%mem{$key} = $ans;
$ans
}
my ($sum1, $sum2);
for $*IN.lines».split(' ') {
my @groups = +«.[1].comb(/\d+/);
$sum1 += solve(.[0].comb, @groups);
$sum2 += solve((.[0] xx 5).join('?').comb, (@groups xx 5).flat.Array);
}
put 'part 1: ', $sum1;
put 'part 2: ', $sum2;
Raku
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