diff --git a/app/src/main/java/ch/nuth/zhaw/exbox/ParallelQuickerSortServer.java b/app/src/main/java/ch/nuth/zhaw/exbox/ParallelQuickerSortServer.java
index d43eeb2..7b3f45b 100644
--- a/app/src/main/java/ch/nuth/zhaw/exbox/ParallelQuickerSortServer.java
+++ b/app/src/main/java/ch/nuth/zhaw/exbox/ParallelQuickerSortServer.java
@@ -26,16 +26,68 @@ public class ParallelQuickerSortServer extends Thread implements CommandExecutor
 
         if (left < right) {
             // TODO Aufgabe 12.3
+            mid = partition(arr, left, right);
+
+            if (mid - left > SPLIT_THRESHOLD) {
+                t1 = new ParallelQuickerSortServer(arr, left, mid - 1);
+                t1.start();
+            } else {
+                quickerSort(arr, left, mid - 1);
+            }
+
+            if (right - mid > SPLIT_THRESHOLD) {
+                t2 = new ParallelQuickerSortServer(arr, mid, right);
+                t2.start();
+            } else {
+                quickerSort(arr, mid, right);
+            }
+        }
+
+        if (t1 != null) {
+            try {
+                t1.join();
+            } catch (InterruptedException e) {}
+        }
+
+        if (t2 != null) {
+            try {
+                t2.join();
+            } catch (InterruptedException e) {}
         }
     }
 
     private void quickerSort(int[] arr, int left, int right) {
         // TODO Aus Aufgabe 12.1 übernehmen
+        if (right - left < insertion_threshold) {
+            insertionSort(arr, left, right);
+        } else {
+            int l = partition(arr, left, right);
+            quickerSort(arr, left, l - 1);
+            quickerSort(arr, l, right);
+        }
     }
 
     private int partition(int[] arr, int left, int right) {
         // TODO Aus Aufgabe 12.1 übernehmen
-		return 0;
+        int pivot = arr[(left + right) / 2];
+
+        while (left <= right) {
+            while (arr[left] < pivot) {
+                left++;
+            }
+
+            while (arr[right] > pivot) {
+                right--;
+            }
+
+            if (left <= right) {
+                swap(arr, left, right);
+                left++;
+                right--;
+            }
+        }
+
+        return left;
     }
 
     private void insertionSort(int[] a, int l, int r) {