added day 1 part 2

Author: mreymann

1_2.php

@@ -0,0 +1,16 @@
+#!/usr/bin/php
+<?php
+error_reporting( -1 );
+$file = trim( file_get_contents( '1_1.in' ) );
+$len = strlen( $file );
+$step = $len / 2;
+$sum = 0;
+$i = 0;
+for ( $j = 0; $j < $len; $j++ ) {
+	$c1 = $file[$i];
+	$k = ( $i + $step ) % $len;
+	$c2 = $file[$k];
+	$i++; 
+	if ( $c1 == $c2 ) $sum += $c1;
+}
+echo "sum: $sum\n";

foo

@@ -0,0 +1,12 @@
+<?php
+/* Recursion via a self-yielding generator.
+ *
+ * Crashes all currently supported PHP versions that support generator delegation (7.0, 7.1).
+ *
+ * A generator delegating to itself, causing a recursion.
+ */
+function a()
+{
+    yield from a();
+}
+foreach(a() as $v);