day02: Solve puzzles

Makefile

@@ -6,6 +6,8 @@ day01:
 	php day01/solve.php input
 
 day02:
+	php day02/solve.php input
+
 day03:
 day04:
 day05:

day02/example.txt

@@ -0,0 +1,6 @@
+forward 5
+down 5
+forward 8
+up 3
+down 8
+forward 2

day02/solve.php

@@ -0,0 +1,66 @@
+<?php
+declare(strict_types=1);
+
+require_once(__DIR__.'/../lib/functions.php');
+
+$entries = getLines(__DIR__.'/'.$argv[1].'.txt');
+
+timedPrintf(
+    '[2021-12-02.1] Resulting position: %d [Time: %ss]',
+    (function (array $entries) : int {
+        $forward = 0;
+        $depth = 0;
+
+        foreach ($entries as $entry) {
+            [ $cmd, $arg ] = explode(' ', $entry, 2);
+
+            switch ($cmd) {
+                case 'forward':
+                    $forward += $arg;
+                    break;
+
+                case 'up':
+                    $depth -= $arg;
+                    break;
+
+                case 'down':
+                    $depth += $arg;
+                    break;
+            }
+        }
+
+        return $forward * $depth;
+    }),
+    $entries
+);
+
+timedPrintf(
+    '[2021-12-02.2] Resulting position: %d [Time: %ss]',
+    (function (array $entries) : int {
+        $forward = 0;
+        $depth = 0;
+        $aim = 0;
+
+        foreach ($entries as $entry) {
+            [ $cmd, $arg ] = explode(' ', $entry, 2);
+
+            switch ($cmd) {
+                case 'forward':
+                    $forward += $arg;
+                    $depth += $aim * $arg;
+                    break;
+
+                case 'up':
+                    $aim -= $arg;
+                    break;
+
+                case 'down':
+                    $aim += $arg;
+                    break;
+            }
+        }
+
+        return $forward * $depth;
+    }),
+    $entries
+);