aoc.pl

#!/usr/bin/perl


use warnings;
use strict;

# IMPORTS
#
use Switch;
use List::Util qw[min max];

# HELPERS
#
my $DEBUG = 0;

sub dprint {
  print @_ if $DEBUG;
}

sub input {
  my $arg = shift;
  my $input = slurp("input.$arg.txt") or return "pants";
  dprint "<INPUT>\n$input</INPUT>";
  return $input;
}

sub slurp {
  open my $fh, '<', shift or return undef;
  $/ = undef;
  my $content = <$fh>;
  $/ = "\n";
  close $fh;
  return $content;
}

sub to_jagged_array {
  my @lines = split '\n', shift;
  my @ary = map {[split /\s/]} @lines;
  return @ary;
}

# SOLUTIONS
#

# Day 1 solution. Yeah it's butt-ugly. No, I'm not sorry.
sub day1 {
  my $sum = 0;
  my $input = input(1);
  for (my $i = 0; $i < length($input); ++$i) {
    $sum += +(substr($input, $i, 1)) if substr($input, $i, 1) eq substr($input, ($i+(2132/2))%2132, 1);
  }
  print "Sum: $sum\n";
}

# Day 2 solution. Still not sorry.
sub day2 {
  my $input = input(2);
  my @lines = split('\n', $input);
  # my $out = join ',', @lines;
  # dprint "Lines: $out\n";
  my $checksum = 0;

  foreach my $line (@lines) {
    my $hi = 0;
    my $lo = 99999;
    my @nums = split(/\s/, $line);
    $hi = max(@nums);
    $lo = min(@nums);


    foreach $a (@nums) {
      foreach $b (@nums) {
        if ($a % $b == 0 && $a != $b) {
          $checksum += $a / $b ;
          dprint "($a/$b)"
        }
      }
    }

    dprint $line . ":: $checksum\n";

  }

  print "Checksum is $checksum\n";
}

# Day 3 solution. TBD.
sub day3 {
  my $input = <<HERE;
This is a test input
It has some lines
And some words.
HERE

  foreach my $line (to_jagged_array($input)) {
    foreach my $el (@$line) {
      print "($el)";
    }
    print "--\n";
  }
}

# ENTRY
#
while ($ARGV[0] =~ /^-(\w)/) {
  my $flag = shift;
  $DEBUG = 'true' if $1 eq 'd';
  dprint "Got flag $flag\n";
}

my @solutions = (
  sub { print "I'm in ur index sploiting ur off-by-ones\n" },
  \&day1,
  \&day2,
  \&day3,
  \&day4,
  \&day5,
  \&day6,
  \&day7,
  \&day8,
  \&day9,
);

if (shift @ARGV eq 'day') {
  my $daynum = shift @ARGV;
  if (exists($solutions[$daynum])) {
    $solutions[$daynum]();
  }
  else {
    print "No solution for day $daynum\n"
  }
}
else {
  foreach my $line (to_jagged_array input(2)) {
    print join ',', @$line;
    print "!!\n";
  }
}