day 1

day1/p1.pl

@@ -0,0 +1,43 @@
+use strict;
+use warnings;
+
+open(my $in, "<", "input1.txt");
+
+my @nums1;
+my @nums2;
+
+# assign numbers correctly
+while (<$in>) {
+    my $trimmed = $_;
+    $trimmed =~ s/\n//g;
+    my @parts = split(/\s{3}/, $trimmed);
+    push(@nums1, $parts[0]);
+    push(@nums2, $parts[1]);
+}
+
+my @sorted1 = sort(@nums1);
+my @sorted2 = sort(@nums2);
+my $total_length = scalar @sorted1;
+#foreach my $i (0..$total_length - 1) {
+#    print "$sorted1[$i]   $sorted2[$i]\n"
+#}
+
+my $result = 0;
+my $similarity = 0;
+
+foreach my $i (0..$total_length - 1) {
+    if ($sorted1[$i] > $sorted2[$i]) {
+        my $distance = $sorted1[$i] - $sorted2[$i];
+        $result = $result + $distance;
+    } elsif ($sorted1[$i] < $sorted2[$i]) {
+        my $distance = $sorted2[$i] - $sorted1[$i];
+        $result = $result + $distance;
+    }
+
+    my @filtered = grep(/$sorted1[$i]/, @sorted2);
+    my $numitems = scalar @filtered;
+    $similarity += $sorted1[$i] * $numitems;
+}
+
+print "Total distance: $result\n";
+print "Total similarity: $similarity\n";

day1/test.txt

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3