Add Y23/Day1

data/Y23/day1/example-part1.txt

@@ -0,0 +1,4 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet

data/Y23/day1/example-part2.txt

@@ -0,0 +1,7 @@
+two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen

src/Y23/Day1.php

@@ -0,0 +1,91 @@
+<?php
+
+namespace trizz\AdventOfCode\Y23;
+
+use trizz\AdventOfCode\Solution;
+
+final class Day1 extends Solution
+{
+    /**
+     * @var array<string,int>
+     */
+    private const NUMBER_STRING = [
+        'one' => 1,
+        'two' => 2,
+        'three' => 3,
+        'four' => 4,
+        'five' => 5,
+        'six' => 6,
+        'seven' => 7,
+        'eight' => 8,
+        'nine' => 9,
+    ];
+
+    public static null|int|string $part1ExampleResult = 142;
+
+    public static null|int|string $part1Result = 53974;
+
+    public static null|int|string $part2ExampleResult = 281;
+
+    public static null|int|string $part2Result = 52840;
+
+    #[\Override]
+    public function part1(array $data): int
+    {
+        $total = 0;
+
+        foreach ($data as $line) {
+            $total += $this->extractNumbersFromLine($line);
+        }
+
+        return $total;
+    }
+
+    #[\Override]
+    public function part2(array $data): int
+    {
+        $total = 0;
+
+        foreach ($data as $line) {
+            $total += $this->extractNumbersFromLineWithText($line);
+        }
+
+        return $total;
+    }
+
+    private function extractNumbersFromLine(string $line): int
+    {
+        preg_match_all('#\d#', $line, $numbers);
+
+        if (empty($numbers[0])) {
+            return 0;
+        }
+
+        $first = $numbers[0][0];
+        $last = $numbers[0][array_key_last($numbers[0])];
+
+        return (int) ($first.$last);
+    }
+
+    private function extractNumbersFromLineWithText(string $line): int
+    {
+        preg_match_all('#\d|'.implode('|', array_keys(self::NUMBER_STRING)).'#', $line, $numbersStart);
+
+        // Same regex, but match everything in reverse, so the last is the first.
+        $keys = implode('|', array_map(static fn (string $k): string => '('.strrev($k).')', array_keys(self::NUMBER_STRING)));
+        preg_match_all('#\d|'.$keys.'#', strrev($line), $numbersEnd);
+
+        $first = $numbersStart[0][0];
+        $last = strrev((string) $numbersEnd[0][0]);
+
+        if (!ctype_digit((string) $first)) {
+            $first = self::NUMBER_STRING[$first];
+        }
+
+        if (!ctype_digit($last)) {
+            $last = self::NUMBER_STRING[$last];
+        }
+
+        return (int) ($first.$last);
+    }
+}