diff --git a/src/ch/zhaw/ads/Storage.java b/src/ch/zhaw/ads/Storage.java
index 384ca82..4e1fd17 100644
--- a/src/ch/zhaw/ads/Storage.java
+++ b/src/ch/zhaw/ads/Storage.java
@@ -6,7 +6,7 @@ import java.util.LinkedList;
 import java.util.List;
 
 public class Storage {
-    public static boolean generationalGCActive = false; // in Aufgabe 2 verwendet
+    public static boolean generationalGCActive = true; // in Aufgabe 2 verwendet
     public static StringBuffer log = new StringBuffer();
     private static List<Collectable> root;
     private static List<Collectable> youngHeap;
@@ -120,26 +120,38 @@ public class Storage {
     }
 
     private static void mark(Collectable cObject) {
-        // TODO Aufgabe 13.1
+        if (!cObject.isMarked()) {
+            cObject.setMark(true);
+            getRefs(cObject).forEach(ref -> mark(ref));
+        }
     }
 
-    private static void sweep() {
-        // TODO Aufgabe 13.1 und Aufgabe 13.2
+    private static void sweep(List<Collectable> heap) {
+        heap.removeIf(obj -> !obj.isMarked());
+        heap.forEach(obj -> obj.setMark(false));
+        //oldHeap.addAll(youngHeap);
+        //youngHeap.clear();
     }
 
     public static void gc() {
+        getRoot().forEach(root -> mark(root));
         if (generationalGCActive) {
             if (youngGenerationOnly) {
                 log.append("\nCollector start young generation only\n");
+                sweep(youngHeap);
+                youngGenerationOnly = false;
             } else {
                 log.append("\nCollector start young and old generation\n");
+                sweep(youngHeap);
+                sweep(oldHeap);
+                youngGenerationOnly = true;
             }
         } else {
             log.append("\nCollector start\n");
+            sweep(youngHeap);
         }
 
-        // TODO Aufgabe 13.1 und Aufgabe 13.2
 
         log.append("Collector end\n");
     }
-}
+}
\ No newline at end of file