AoC 2017 days 11 to 15

[aoc.git] / 2017 / 29.pl

diff --git a/2017/29.pl b/2017/29.pl
new file mode 100755 (executable)
index 0000000..fa9c3cc
--- /dev/null
+++ b/2017/29.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my @start = (883, 879);
+# my @start = (65, 8921);
+my @f = (16807, 48271);
+
+sub gen {
+       my ($i,$gen) = @_;
+       $start[$i] = $start[$i] * $f[$i] % 2147483647;
+       return $start[$i] & 0xFFFF;
+}
+my $matches = 0;
+for (1 .. 40_000_000) {
+       $matches++ if gen(0, $_) == gen(1, $_);
+}
+
+say $matches;