AoC 2017 days 11 to 15

diff --git a/2017/21.pl b/2017/21.pl
new file mode 100755 (executable)
index 0000000..9fc2bfe
--- /dev/null
+++ b/2017/21.pl
@@ -0,0 +1,43 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my ($x, $y) = (0, 0);
+
+my @path = split /[,\s]/, <>;
+
+#   |/
+#   o
+#  /|
+# x y
+for my $dir (@path) {
+       if ($dir eq 's') {
+               $y--;
+       } elsif ($dir eq 'n') {
+               $y++;
+       } elsif ($dir eq 'ne') {
+               $x++;
+       } elsif ($dir eq 'nw') {
+               $x--;
+               $y++;
+       } elsif ($dir eq 'se') {
+               $x++;
+               $y--;
+       } elsif ($dir eq 'sw') {
+               $x--;
+       }
+}
+
+my $dist;
+if ($x >= 0 && $y >= 0 || $x <= 0 && $y <= 0) {
+       $dist = abs($x + $y);
+} elsif (abs($x) >= abs($y)) {
+       $dist = abs($x);
+} else {
+       $dist = abs($y);
+}
+
+say $dist;
+       
+

diff --git a/2017/22.pl b/2017/22.pl
new file mode 100755 (executable)
index 0000000..dcaa0da
--- /dev/null
+++ b/2017/22.pl
@@ -0,0 +1,51 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my ($x, $y) = (0, 0);
+
+my @path = split /[,\s]/, <>;
+
+#   |/
+#   o
+#  /|
+# x y
+
+sub dist {
+       my ($x,$y) = @_;
+       my $dist;
+       if ($x >= 0 && $y >= 0 || $x <= 0 && $y <= 0) {
+               $dist = abs($x + $y);
+       } elsif (abs($x) >= abs($y)) {
+               $dist = abs($x);
+       } else {
+               $dist = abs($y);
+       }
+       return $dist;
+}
+
+my $max;
+for my $dir (@path) {
+       if ($dir eq 's') {
+               $y--;
+       } elsif ($dir eq 'n') {
+               $y++;
+       } elsif ($dir eq 'ne') {
+               $x++;
+       } elsif ($dir eq 'nw') {
+               $x--;
+               $y++;
+       } elsif ($dir eq 'se') {
+               $x++;
+               $y--;
+       } elsif ($dir eq 'sw') {
+               $x--;
+       }
+       my $d = dist($x,$y);
+       $max = $d if !$max || $max < $d;
+}
+
+say $max;
+       
+

diff --git a/2017/23.pl b/2017/23.pl
new file mode 100755 (executable)
index 0000000..73a2e81
--- /dev/null
+++ b/2017/23.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my %zero;
+my %graph;
+$; = ',';
+
+while (<>) {
+       chomp;
+       my ($src, @dsts) = /(\d+)/g;
+       $graph{$src} = [ @dsts ];
+}
+
+
+sub walk {
+       my ($node) = @_;
+
+       for my $neigh (@{ $graph{$node} }) {
+               next if $zero{$neigh}++;
+               walk($neigh);
+       }
+}
+
+walk(0);
+say scalar keys %zero;

diff --git a/2017/24.pl b/2017/24.pl
new file mode 100755 (executable)
index 0000000..7b85e56
--- /dev/null
+++ b/2017/24.pl
@@ -0,0 +1,32 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my %zero;
+my %graph;
+$; = ',';
+
+while (<>) {
+       chomp;
+       my ($src, @dsts) = /(\d+)/g;
+       $graph{$src} = [ @dsts ];
+}
+
+
+sub walk {
+       my ($node) = @_;
+
+       for my $neigh (@{ $graph{$node} }) {
+               next if $zero{$neigh}++;
+               walk($neigh);
+       }
+}
+
+my $comp;
+for my $node (keys %graph) {
+       next if $zero{$node};
+       walk($node);
+       $comp++;
+}
+say $comp;

diff --git a/2017/25.pl b/2017/25.pl
new file mode 100755 (executable)
index 0000000..37f5ce3
--- /dev/null
+++ b/2017/25.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+use List::Util qw(max);
+
+my %layers = map { /(\d+): (\d+)/ } <>;
+my $max_l = max keys %layers;
+
+my $severity = 0;
+for my $pos (0 .. $max_l) {
+       next if !defined $layers{$pos};
+       next if $pos % (2 * $layers{$pos} - 2);
+       say "caught at $pos";
+       $severity += $pos * $layers{$pos};
+}
+
+say $severity;
+

diff --git a/2017/26.pl b/2017/26.pl
new file mode 100755 (executable)
index 0000000..d3b6957
--- /dev/null
+++ b/2017/26.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+use List::Util qw(max);
+
+my %layers = map { /(\d+): (\d+)/ } <>;
+my $max_l = max keys %layers;
+
+my $delay = -1;
+DELAY:
+while (1) {
+       $delay++;
+       for my $pos (0 .. $max_l) {
+               next if !defined $layers{$pos};
+               next if ($pos+$delay) % (2 * $layers{$pos} - 2);
+               next DELAY;
+       }
+       last;
+}
+
+say $delay;
+

diff --git a/2017/27.pl b/2017/27.pl
new file mode 100755 (executable)
index 0000000..dd0a244
--- /dev/null
+++ b/2017/27.pl
@@ -0,0 +1,55 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my $in = 'stpzcrnm';
+# my $in = 'flqrgnkx';
+
+sub knot {
+       my $line = shift;
+       my @l = map { ord } split //, $line;
+       push @l, 17, 31, 73, 47, 23;
+
+       my $pos = 0;
+       my $skip = 0;
+       # my @nodes = (0 .. 4);
+       my @nodes = (0 .. 255);
+       my $n = @nodes;
+
+       for (1 .. 64) {
+               for my $i (@l) {
+                       my $end = $pos + $i;
+                       my @to_rev;
+                       # say "pos=$pos skip $skip i=$i ", join(',', @nodes);
+                       if ($end > $n) {
+                               push @to_rev, splice @nodes, $pos;
+                               push @to_rev, splice @nodes, 0, $end - $n;
+                               @to_rev = reverse @to_rev;
+                               # say "to_rev = ", join(',', @to_rev);
+                               unshift @nodes, splice @to_rev, @to_rev-($end-$n);
+                               push @nodes, @to_rev;
+                       } else {
+                               push @to_rev, splice @nodes, $pos, $i;
+                               splice @nodes, $pos, 0, reverse @to_rev;
+                       }
+                       $pos += $i + $skip++;
+                       $pos -= $n while $pos >= $n;
+               }
+       }
+
+       my $hash = '';
+       while (my @s = splice (@nodes, 0, 16)) {
+               my $x = 0;
+               $x ^= $_ for @s;
+               $hash .= sprintf("%08b", $x);
+       }
+       return $hash;
+}
+
+my $used = 0;
+for my $row (0 .. 127) {
+       my $h = knot("$in-$row");
+       $used++ for $h =~ /1/g;
+}
+say $used;

diff --git a/2017/28.pl b/2017/28.pl
new file mode 100755 (executable)
index 0000000..0d742d6
--- /dev/null
+++ b/2017/28.pl
@@ -0,0 +1,82 @@
+#!/usr/bin/perl
+
+use v5.30;
+use strict;
+
+my $in = 'stpzcrnm';
+# my $in = 'flqrgnkx';
+
+sub knot {
+       my $line = shift;
+       my @l = map { ord } split //, $line;
+       push @l, 17, 31, 73, 47, 23;
+
+       my $pos = 0;
+       my $skip = 0;
+       # my @nodes = (0 .. 4);
+       my @nodes = (0 .. 255);
+       my $n = @nodes;
+
+       for (1 .. 64) {
+               for my $i (@l) {
+                       my $end = $pos + $i;
+                       my @to_rev;
+                       # say "pos=$pos skip $skip i=$i ", join(',', @nodes);
+                       if ($end > $n) {
+                               push @to_rev, splice @nodes, $pos;
+                               push @to_rev, splice @nodes, 0, $end - $n;
+                               @to_rev = reverse @to_rev;
+                               # say "to_rev = ", join(',', @to_rev);
+                               unshift @nodes, splice @to_rev, @to_rev-($end-$n);
+                               push @nodes, @to_rev;
+                       } else {
+                               push @to_rev, splice @nodes, $pos, $i;
+                               splice @nodes, $pos, 0, reverse @to_rev;
+                       }
+                       $pos += $i + $skip++;
+                       $pos -= $n while $pos >= $n;
+               }
+       }
+
+       my $hash = '';
+       while (my @s = splice (@nodes, 0, 16)) {
+               my $x = 0;
+               $x ^= $_ for @s;
+               $hash .= sprintf("%08b", $x);
+       }
+       return $hash;
+}
+
+my @prev = (0) x 128;
+my %regions;
+my $nr = 1;
+for my $row (0 .. 127) {
+       my $h = knot("$in-$row");
+       my @line = split //, $h;
+       my @nl = (0) x 128;
+       for my $x (0 .. 127) {
+               next if $line[$x] == '0';
+
+               if ($prev[$x]) {
+                       $nl[$x] = $prev[$x];
+               } elsif ($x && $nl[$x-1]) {
+                       $nl[$x] = $nl[$x-1];
+               } else {
+                       $nl[$x] = $nr;
+                       $regions{$nr} = 1;
+                       $nr++;
+               }
+               if ($x && $nl[$x-1] && $nl[$x-1] != $nl[$x]) {
+                       my $old = $nl[$x-1];
+                       delete $regions{$old};
+                       for (0 .. 127) {
+                               $nl[$_] = $nl[$x] if $nl[$_] == $old;
+                               $prev[$_] = $nl[$x] if $prev[$_] == $old;
+                       }
+               }
+       }
+       @prev = @nl;
+}
+
+say scalar keys %regions;
+

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;

diff --git a/2017/30.pl b/2017/30.pl
new file mode 100755 (executable)
index 0000000..8dfb269
--- /dev/null
+++ b/2017/30.pl
@@ -0,0 +1,22 @@
+#!/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) = @_;
+       do {
+               $start[$i] = $start[$i] * $f[$i] % 2147483647
+       } while ($start[$i] % (1 << (2+$i)) != 0);
+       return $start[$i] & 0xFFFF;
+}
+my $matches = 0;
+for (1 .. 5_000_000) {
+       $matches++ if gen(0, $_) == gen(1, $_);
+}
+
+say $matches;