adventofcode/2015/20/2.pl

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Perl
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2017-12-13 00:55:17 +00:00
use 5.20.0;
use List::AllUtils qw/ sum /;
use Math::Prime::Util ':all';
my $x = 34000000;
my $house = 1;
$house++ while( nbr_gifts($house) < $x );
say $house;
sub nbr_gifts {
my $n = shift;
11 * sum grep { 50 * $_ >= $n } divisors($n);
}