✨ Finit le jour 2 et commence le 1 et le 3

day_2/part_1.php

@@ -0,0 +1,28 @@
+<?php
+
+$intervals = array_map(fn($interval) => explode('-', $interval), explode(',', file_get_contents('./input.txt')));
+
+$invalids = [];
+
+foreach ($intervals as $interval) {
+    [$start, $end] = $interval;
+    $current = $start;
+    while ($current <= $end) {
+        if (is_invalid($current)) {
+            $invalids[] = $current;
+        }
+
+        $current++;
+    }
+}
+
+function is_invalid($current): bool {
+    if (strlen($current) % 2 !== 0) {
+        return false;
+    }
+
+    $middle = strlen($current) / 2;
+    return substr($current, 0, $middle) === substr($current, $middle);
+}
+
+echo array_sum($invalids);

day_2/part_2.php

@@ -0,0 +1,37 @@
+<?php
+
+$intervals = array_map(fn($interval) => explode('-', $interval), explode(',', file_get_contents('./input.txt')));
+
+$invalids = [];
+
+foreach ($intervals as $interval) {
+    [$start, $end] = $interval;
+    $current = $start;
+    while ($current <= $end) {
+        if (is_invalid($current)) {
+            $invalids[] = $current;
+        }
+
+        $current++;
+    }
+}
+
+function is_invalid(string $current): bool {
+    for ($i = 1, $l = strlen($current); $i < $l; $i++) {
+        $parts = str_split($current, $i);
+        $is_equals = true;
+        for ($j = 0, $m = count($parts) - 1; $j < $m; $j++) {
+            if ($parts[$j] !== $parts[$j + 1]) {
+                $is_equals = false;
+                continue;
+            }
+        }
+        if ($is_equals) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+echo array_sum($invalids);