✨ Finit le 3eme jour

day_3/part_1.php

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+<?php
+
+// je récupère la map de base
+$map = array_map('str_split', explode("\n", file_get_contents('input.txt')));
+$height = count($map);
+$length = count($map[0]);
+
+// je la multiplie pour qu'elle soit complète
+$multiply_by = ceil($height / $length) * 4;
+array_walk($map, static function(&$row) use ($multiply_by) {
+    $row = str_split(str_repeat(implode('', $row), $multiply_by));
+});
+$height = count($map);
+$length = count($map[0]);
+
+// je la visite et compte les arbres
+$right = 0;
+$down = 0;
+$count_trees = 0;
+while ($right < $length && $down < $height) {
+    if ($map[$down][$right] === '#') {
+        $count_trees++;
+    }
+
+    $right += 3;
+    ++$down;
+}
+
+echo $count_trees;

day_3/part_2.php

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+<?php
+
+// je récupère la map de base
+$map = array_map('str_split', explode("\n", file_get_contents('input.txt')));
+$height = count($map);
+$length = count($map[0]);
+
+// je la multiplie pour qu'elle soit complète
+$multiply_by = ceil($height / $length) * 8;
+array_walk($map, static function(&$row) use ($multiply_by) {
+    $row = str_split(str_repeat(implode('', $row), $multiply_by));
+});
+$height = count($map);
+$length = count($map[0]);
+
+// je la visite et compte les arbres
+$tests = [
+    ['Right' => 1, 'down' => 1],
+    ['Right' => 3, 'down' => 1],
+    ['Right' => 5, 'down' => 1],
+    ['Right' => 7, 'down' => 1],
+    ['Right' => 1, 'down' => 2],
+];
+
+$result = 1;
+foreach ($tests as $i => $test) {
+    $right = 0;
+    $down = 0;
+    $count_trees = 0;
+    while ($right < $length && $down < $height) {
+        if ($map[$down][$right] === '#') {
+            $count_trees++;
+        }
+
+        $right += $test['Right'];
+        $down += $test['down'];
+    }
+
+//    echo sprintf('Trouvé %u arbres sur le parcours %u', $count_trees, $i);
+    $result *= $count_trees;
+}
+
+
+echo $result;