✨ Add day 16 part 1

Too slow for part 2

day_16/part_1.php

@@ -0,0 +1,65 @@
+<?php
+
+function flatten(array $array)
+{
+    $result = [];
+    foreach ($array as $value) {
+        $key = current(array_keys($value));
+        $result[$key] = $value[$key];
+    }
+
+    return $result;
+}
+
+function generate_patterns($sequence_length)
+{
+    $base_pattern = [0, 1, 0, -1];
+    $base_pattern_length = count($base_pattern);
+    $patterns = [];
+    for($i = 0; $i <= $sequence_length; $i++) {
+        $current_pattern = [];
+        $j = $i + 1;
+        // $i = 0, pattern = $base_pattern en boucle
+        // $i = 1, pattern = chaque base pattern * $j (en virant le 1er)
+        for ($m = 0; $m <= $sequence_length / $base_pattern_length; $m++) {
+            foreach ($base_pattern as $kValue) {
+                if (array_key_exists($i, $current_pattern)) {
+                    $current_pattern[$i] .= str_repeat($kValue.',', $j);
+                } else {
+                    $current_pattern[$i] = str_repeat($kValue.',', $j);
+                }
+            }
+        }
+
+        $patterns[] = substr($current_pattern[$i], 2);
+    }
+
+    unset($current_pattern, $i, $j, $m, $k);
+
+    return $patterns;
+}
+
+$sequence = str_split(file_get_contents('input.txt'));
+$sequence_length = count($sequence);
+
+echo "generating patterns…\n";
+$patterns = generate_patterns($sequence_length);
+echo "patterns generated\n";
+for ($loops = 0; $loops < 100; $loops++) {
+
+    $numbers = [];
+    foreach ($sequence as $i => $number) {
+        $line_pattern = explode(',', $patterns[$i]);
+        $numbers[] = substr(
+            array_sum(
+                array_map(function($number, $pattern) use ($line_pattern) {
+                    return $number * $line_pattern[$pattern];
+                }, $sequence, range(0, $sequence_length))
+            ), -1
+        );
+    }
+    $sequence = $numbers;
+    echo "loop $loops finished\n";
+}
+
+echo implode('', array_slice($sequence, 0, 8));