2025 day 6 in PHP

2025/day06/README.md

@@ -0,0 +1,10 @@
+# Day 06: PHP
+
+Simple and straight-forward. This is a normal programming language.
+
+
+```console
+$ ./solve.php sample.txt
+Part1: 4277556
+Part2: 3263827
+```

2025/day06/sample.txt

@@ -0,0 +1,4 @@
+123 328  51 64 
+ 45 64  387 23 
+  6 98  215 314
+*   +   *   +  

2025/day06/solve.php

@@ -0,0 +1,81 @@
+#!/usr/bin/env php
+<?php
+
+if ($argc < 2) {
+    echo "Usage: {$argv[0]} INPUT\n";
+    exit(1);
+}
+
+$input = file($argv[1]);
+
+function part1(string ...$input): int {
+    $lines = [];
+
+    foreach ($input as $line) {
+        $lines[] = preg_split('/\s+/', $line, -1, PREG_SPLIT_NO_EMPTY);
+    }
+
+    $lines = array_reverse($lines);
+    $cols = count($lines[0]);
+    $rows = count($lines);
+
+    $sum = 0;
+
+    for ($col = 0; $col < $cols; ++$col) {
+        if ($lines[0][$col] === '+') {
+            $acc = 0;
+            for ($row  = 1; $row < $rows; ++$row) {
+                $acc += (int) $lines[$row][$col];
+            }
+        } else {
+            $acc = 1;
+            for ($row  = 1; $row < $rows; ++$row) {
+                $acc *= (int) $lines[$row][$col];
+            }
+        }
+
+        $sum += $acc;
+    }
+
+    return $sum;
+}
+
+function part2(string ...$lines): int {
+    $cols = strlen($lines[0]);
+    $rows = count($lines);
+    $numbers = array_fill(0, $cols, "");
+
+    for ($row = 0; $row < $rows - 1; ++$row) {
+        foreach (str_split($lines[$row]) as $col => $c) {
+            if ($c !== ' ') {
+                $numbers[$col] .= $c;
+            }
+        }
+    }
+
+    $sum = 0;
+
+    foreach (str_split($lines[$rows - 1]) as $col => $c) {
+        switch ($c) {
+            case '+':
+                $acc = 0;
+                for ($i = $col; $i < $cols && $numbers[$i] !== ""; ++$i) {
+                    $acc += (int) $numbers[$i];
+                }
+                $sum += $acc;
+                break;
+            case '*':
+                $acc = 1;
+                for ($i = $col; $i < $cols && $numbers[$i] !== ""; ++$i) {
+                    $acc *= (int) $numbers[$i];
+                }
+                $sum += $acc;
+                break;
+        }
+    }
+
+    return $sum;
+}
+
+echo "Part1: " . part1(...$input) . "\n";
+echo "Part2: " . part2(...$input) . "\n";