Year 2015

[aoc.git] / 2015 / 39.pl

diff --git a/2015/39.pl b/2015/39.pl
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+#!/usr/bin/perl -w
+
+use v5.16;
+use strict;
+
+my $in = 33100000;
+
+my $maxh = $in/10;
+
+my @houses = (10) x $maxh;
+for my $elf (2 .. $maxh) {
+       my $h = $elf;
+       do {
+               $houses[$h] += 10*$elf;
+               $h += $elf;
+       } while ($h <= $maxh);
+}
+
+for my $h (1 .. $maxh) {
+       next if $houses[$h] < $in;
+       say $h;
+       last;
+}
+