6th day 2nd part

06/part2.php

@@ -0,0 +1,18 @@
+<?php
+
+$input = file('input', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
+$input = explode(',', $input[0]);
+
+$fishes = array_fill(0, 9, 0);
+foreach ($input as $fish) {
+    $fishes[$fish]++;
+}
+for ($i = 1; $i <= 256; $i++) {
+    $newBorns = $fishes[0];
+    for ($j = 1; $j <= 8; $j++) {
+        $fishes[$j - 1] = $fishes[$j];
+    }
+    $fishes[6] += $newBorns;
+    $fishes[8] = $newBorns;
+}
+echo array_sum($fishes); //1746710169834