Day 2, Part 1
use strict;
use List::Util qw( min max );
open(FH, '<', $ARGV[0]) or die $!;
my @lines;
while (<FH>) {
my @report = split /\s/, $_;
push @lines, \@report;
}
close FH;
sub in_range {
my $diff = max($_[0], $_[1]) - min($_[0], $_[1]);
return $diff >= 1 && $diff <= 3;
}
sub is_safe {
my $prev = @$_[0];
my $dir = 0;
for (my $i = 1; $i < scalar @$_; ++$i) {
my $el = @$_[$i];
if ($el > $prev) {
return 0 unless $dir >= 0;
$dir = 1;
} elsif ($el < $prev) {
return 0 unless $dir <= 0;
$dir = -1;
}
return 0 unless in_range $prev, $el;
$prev = $el;
}
return 1;
}
sub part1 {
my $safe_reports = 0;
foreach (@_) {
$safe_reports++ if is_safe @$_;
}
return $safe_reports;
}
print 'Part 1: ', part1(@lines), "\n";
My part 2 solution didn't work with the real input but worked with all the test cases I threw at it, so I couldn't figure out what was wrong with it and I'm too lazy to debug any more right now.
1 day old and over 1000 kudos. Holy shit.