Add day 2 '22 solution

src/Y22/Day2.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace trizz\AdventOfCode\Y22;
+
+use trizz\AdventOfCode\Solution;
+use trizz\AdventOfCode\Y22\Day2\RPS;
+
+final class Day2 extends Solution
+{
+    public static int|string|null $part1ExampleResult = 15;
+
+    public static int|string|null $part1Result = 10994;
+
+    public static int|string|null $part2ExampleResult = 12;
+
+    public static int|string|null $part2Result = 12526;
+
+    public function part1(array $data): int
+    {
+        $score = 0;
+        foreach ($data as $round) {
+            [$opponentDraw, $ownDraw] = explode(' ', $round);
+            $ownDraw = RPS::fromPuzzleInput($ownDraw);
+            $opponentDraw = RPS::fromPuzzleInput($opponentDraw);
+            $score += $this->calculateScore($ownDraw, $opponentDraw);
+        }
+
+        return $score;
+    }
+
+    public function part2(array $data): int
+    {
+        $score = 0;
+        foreach ($data as $round) {
+            [$opponentDraw, $expectedResult] = explode(' ', $round);
+            $opponentDraw = RPS::fromPuzzleInput($opponentDraw);
+
+            $score += match ($expectedResult) {
+                'X' => $this->calculateScore($opponentDraw->losingOpposite(), $opponentDraw),
+                'Y' => $this->calculateScore($opponentDraw, $opponentDraw),
+                'Z' => $this->calculateScore($opponentDraw->winningOpposite(), $opponentDraw),
+                default => 0,
+            };
+        }
+
+        return $score;
+    }
+
+    private function calculateScore(RPS $ownDraw, RPS $opponentDraw): int
+    {
+        // Win
+        if ($ownDraw->losingOpposite() === $opponentDraw) {
+            return $ownDraw->score() + 6;
+        }
+
+        // Lost
+        if ($ownDraw->winningOpposite() === $opponentDraw) {
+            return $ownDraw->score();
+        }
+
+        // Draw.
+        return $ownDraw->score() + 3;
+    }
+}

src/Y22/Day2/RPS.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace trizz\AdventOfCode\Y22\Day2;
+
+enum RPS
+{
+    case ROCK;
+
+    case PAPER;
+
+    case SCISSORS;
+
+    public function score(): int
+    {
+        return match ($this) {
+            self::ROCK => 1,
+            self::PAPER => 2,
+            self::SCISSORS => 3,
+        };
+    }
+
+    public function winningOpposite(): RPS
+    {
+        return match ($this) {
+            self::ROCK => self::PAPER,
+            self::PAPER => self::SCISSORS,
+            self::SCISSORS => self::ROCK,
+        };
+    }
+
+    public function losingOpposite(): RPS
+    {
+        return match ($this) {
+            self::ROCK => self::SCISSORS,
+            self::PAPER => self::ROCK,
+            self::SCISSORS => self::PAPER,
+        };
+    }
+
+    public static function fromPuzzleInput(string $value): RPS
+    {
+        return match ($value) {
+            'A', 'X' => self::ROCK,
+            'B', 'Y' => self::PAPER,
+            'C', 'Z' => self::SCISSORS,
+            default => throw new \LogicException('Invalid value.'),
+        };
+    }
+}