aoc2021

commit a59553c92fd8f85cd09274d8756a2cf61f540b74
parent 7d9faeae1dfb12f9efc9ceb07e99b14623de790b
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Tue, 21 Dec 2021 15:23:24 +0000

initial commit for day09-2.pl

Diffstat:
A
day09-2.pl
 | 
34
++++++++++++++++++++++++++++++++++

1 file changed, 34 insertions(+), 0 deletions(-)
diff --git a/day09-2.pl b/day09-2.pl
@@ -0,0 +1,34 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use v5.22;
+use Data::Dumper;
+
+sub find_basin {
+  my ($row, $column, $heightmap_ref) = @_;
+}
+
+my @heightmap = map{ [m/\d/g, 9] } <>; # add extra column of 9s
+my $columns = @{$heightmap[0]};
+push @heightmap => [ (9) x $columns ]; # add extra row of 9s
+my $rows = @heightmap;
+my $risk_level = 0;
+
+foreach my $row (0 .. $rows - 2) { # don't care about last row that we added
+  foreach my $column (0 .. $columns - 2) { # don't care about the last column
+    my $height = $heightmap[$row][$column];
+    my $lowpoint = 1; # true
+    foreach my $offset ([0, -1], [0, 1], [-1, 0], [1, 0]) {
+      if ($height >=
+          $heightmap[$row + $offset->[0]][$column + $offset->[1]]) {
+        $lowpoint = 0; # set to false
+        last;
+      }
+    }
+    # found low point
+    $risk_level += $height + 1 if $lowpoint;
+  }
+}
+
+say $risk_level;