From: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Date: Tue, 10 Dec 2024 06:00:51 +0000 (+0100)
Subject: Day 9: array splicing. Quite ugly.
X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=commitdiff_plain;h=cdc7d431e6feed62fbb8eaf6610f6d952fd6edab;p=aoc.git

Day 9: array splicing. Quite ugly.
---

diff --git a/2024/17.pl b/2024/17.pl
new file mode 100755
index 0000000..057c733
--- /dev/null
+++ b/2024/17.pl
@@ -0,0 +1,42 @@
+#!/usr/bin/perl -w
+
+use v5.40;
+
+chomp (my $line = <>);
+my $i = 0;
+my @blk = map { [ $i++, $_ ] } split //, $line;
+
+my $bno = 0;
+my $csum;
+sub add_blk($id, $count) {
+	die "$id" if $id % 2;
+	$id = $id/2;
+	$csum += ($bno++ * $id) for (1 .. $count);
+}
+
+my $freesp = 0;
+while (@blk) {
+	if (!$freesp) {
+		my $b = shift @blk;
+		add_blk(@$b);
+		last if !@blk;
+		$freesp = (shift @blk)->[1];
+	}
+
+	my ($eid, $ecnt) = $blk[-1]->@*;
+	if ($freesp < $ecnt) {
+		$blk[-1]->[1] -= $freesp;
+		add_blk($blk[-1]->[0], $freesp);
+		$freesp = 0;
+	} else {
+		last if !@blk;
+		my $b = pop @blk;
+		add_blk(@$b);
+		$freesp -= $b->[1];
+		last if !@blk;
+		pop @blk;
+	}
+}
+
+say $csum;
+
diff --git a/2024/18.pl b/2024/18.pl
new file mode 100755
index 0000000..fc01063
--- /dev/null
+++ b/2024/18.pl
@@ -0,0 +1,51 @@
+#!/usr/bin/perl -w
+
+use v5.40;
+
+chomp (my $line = <>);
+my $i = 0;
+my @blk = map { [ $i++, $_ ] } split //, $line;
+
+my $mfile = $#blk;
+my %seen;
+while ($mfile) {
+	my ($id, $count) = $blk[$mfile]->@*;
+	if ($seen{$id}++) {
+		$mfile -= 2;
+		next;
+	}
+
+	my $freesp = 1;
+	while ($freesp < $mfile) {
+		if ($blk[$freesp]->[1] >= $count) {
+			if ($mfile < $#blk) {
+				my $free = $blk[$mfile+1]->[1];
+				splice @blk, $mfile+1, 1;
+				if ($mfile) {
+					$blk[$mfile-1]->[1] += $free + $count;
+				}
+			}
+			splice @blk, $mfile, 1;
+			my $free = $blk[$freesp]->[1];
+			splice @blk, $freesp, 1, [ -1, 0 ], [ $id, $count ],
+				[ -1, $free - $count ];
+			last;
+		}
+		$freesp += 2;
+	}
+}
+
+my $csum = 0;
+$i = 0;
+my $bno = 0;
+while ($i < @blk) {
+	my ($id, $count) = $blk[$i++]->@*;
+	$id /= 2;
+	$csum += ($bno++ * $id) for (1 .. $count);
+	
+	last if $i >= @blk;
+	($id, $count) = $blk[$i++]->@*;
+	$bno += $count;
+}
+say $csum;
+