1 files changed, 68 insertions, 0 deletions

diff --git a/2019/day3/wires.pl b/2019/day3/wires.pl
new file mode 100644
index 0000000..fa4ddf1
--- /dev/null
+++ b/2019/day3/wires.pl
@@ -0,0 +1,68 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use List::Util 'min';
+# use Smart::Comments;
+use Data::Dumper;
+
+sub manhattan_distance {
+    my $ref = shift;
+    my ($x, $y) = @{$ref};
+
+    return abs(0 - $x) + abs(0 - $y);
+}
+
+sub pedometer {
+    my $ref = shift;
+    my ($x, $y, $step_1, $step_2) = @{$ref};
+    return $step_1 + $step_2;
+}
+
+my %directions = (
+    'U' => [0, 1],
+    'D' => [0,-1],
+    'R' => [1, 0],
+    'L' => [-1,0]
+);
+
+my $turn = 0;
+my @intersections = ();
+my %map;
+
+while(<>) {
+    chomp;
+    my @path = split /,/;
+    my @coord = (0,0); # Starting point
+    my $num_steps = 0;
+
+    if (!$turn){
+        foreach my $way (@path) {
+            my ($dir, $speed) = ($1, $2) if ($way =~ /(\w)(\d+)/) or die "$!";
+            for (1..$speed) {
+                $coord[0] += @{$directions{$dir}}[0];
+                $coord[1] += @{$directions{$dir}}[1];
+                $num_steps++;
+                $map{"$coord[0],$coord[1]"} = $num_steps;
+            }
+        }
+        $turn = !$turn;
+    } else {
+        foreach my $way (@path) {
+            my ($dir, $speed) = ($1, $2) if ($way =~ /(\w)(\d+)/) or die "$!";
+            for (1..$speed) {
+                $coord[0] += @{$directions{$dir}}[0];
+                $coord[1] += @{$directions{$dir}}[1];
+                $num_steps++;
+                if (exists $map{"$coord[0],$coord[1]"}) {
+                    push @intersections, [@coord,$num_steps,$map{"$coord[0],$coord[1]"}];
+                }
+            }
+        }
+    }
+}
+
+# print Dumper \@intersections;
+print(min(map {pedometer($_);} @intersections));
+
+