aoc2021

commit 77472dacbfefdef120a61b469fbe5849d7558f86
parent 685fbd8e10248f7bf98b0b64868eca839d8b2282
Author: Samir Parikh <noreply@samirparikh.com>
Date:   Fri, 17 Dec 2021 20:58:09 +0000

update day07-2.pl with notes about what I still need to do and correct

Diffstat:
A
day07-2.pl
 | 
52
++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 52 insertions(+), 0 deletions(-)
diff --git a/day07-2.pl b/day07-2.pl
@@ -0,0 +1,52 @@
+#!/usr/bin/env perl
+
+# i am doing this wrong
+# I am assuming that the only positions they crabs can align on are ones
+# that they already occupy.  I got luck with Part 1 in that one of the crabs
+# already occupied the winning answer
+# for Part 2, it's possible that the winning position that consumes the least
+# amoutn of fuel is a position that no crab initially occupies
+# I need to find the range of positions (min/max) and use that as the ranges
+# for the x and y loops
+use strict;
+use warnings;
+use v5.22;
+
+sub get_filehandle {
+    if (@ARGV !=1) {
+        die "Usage: $0 [input-filename]";
+    }
+    my $input_filename = $ARGV[0];
+    open my $filehandle, '<', $input_filename or
+        die "Could not open input file $input_filename: $!";
+    return $filehandle;
+}
+
+sub get_numbers {
+    my $fh = shift;
+    chomp( my $numbers = ( <$fh> ) );
+    return (split( ",", $numbers));
+}
+
+# Advent of Code 2021 Day 07
+my $filehandle  = get_filehandle();
+my @numbers     = get_numbers($filehandle);
+my $min_fuel_cost;
+my $horiz_pos;
+
+foreach my $x (0 .. $#numbers) {
+    my $fuel_cost = 0;
+    foreach my $y (0 .. $#numbers) {
+        my $n = abs($numbers[$x] - $numbers[$y]);
+        $fuel_cost += $n * ($n + 1) / 2;
+        say "move from $numbers[$y] to $numbers[$x]: $n";
+    }
+    say "------------";
+    if (!defined($min_fuel_cost) || $fuel_cost < $min_fuel_cost) {
+        $min_fuel_cost = $fuel_cost;
+        $horiz_pos = $x;
+    }
+    say "TOTAL cost to move to position $x is $fuel_cost";
+}
+
+say "winning position is $horiz_pos with cost of $min_fuel_cost";