From 4683636700de252189bd3b007c0f2a00fe6b5b23 Mon Sep 17 00:00:00 2001
From: "navid.sassan" <navid.sassan@linuxfabrik.ch>
Date: Mon, 14 Dec 2020 16:10:22 +0100
Subject: [PATCH] solved s12 ex3

---
 .../ch/zhaw/ads/ThreadQuickerSortServer.java  | 101 ++++++++++++++++++
 .../zhaw/ads/ThreadQuickerSortServerTest.java |  19 ++++
 2 files changed, 120 insertions(+)
 create mode 100644 12/src/main/java/ch/zhaw/ads/ThreadQuickerSortServer.java
 create mode 100644 12/src/test/java/ch/zhaw/ads/ThreadQuickerSortServerTest.java

diff --git a/12/src/main/java/ch/zhaw/ads/ThreadQuickerSortServer.java b/12/src/main/java/ch/zhaw/ads/ThreadQuickerSortServer.java
new file mode 100644
index 0000000..740e0ac
--- /dev/null
+++ b/12/src/main/java/ch/zhaw/ads/ThreadQuickerSortServer.java
@@ -0,0 +1,101 @@
+package ch.zhaw.ads;
+
+import java.util.Random;
+import java.util.concurrent.*;
+import java.util.function.Consumer;
+import java.util.concurrent.atomic.AtomicIntegerArray;
+
+public class ThreadQuickerSortServer implements CommandExecutor {
+    int QUICKSORT_THRESHOLD = 70;
+
+    private ExecutorService threadPool;
+    private ConcurrentLinkedQueue<Future> futureList;
+
+    @Override
+    public String execute(String command) {
+        AtomicIntegerArray testdata = new AtomicIntegerArray(1000);
+        Random random = new Random();
+        for (int i=0; i < testdata.length(); i++) {
+            testdata.set(i, random.nextInt(1000000));
+        }
+
+
+        int parallelism = java.lang.Runtime.getRuntime().availableProcessors() * 2;
+        threadPool = Executors.newFixedThreadPool(parallelism);
+
+        futureList = new ConcurrentLinkedQueue<Future>();
+        quickSort(testdata);
+
+        try {
+            while (!futureList.isEmpty()) {
+                    futureList.poll().get();
+            }
+        } catch (InterruptedException e) {
+            System.out.println("interrupted!");
+        } catch (ExecutionException e) {
+            System.out.println("failed to execute!");
+            e.printStackTrace();
+        }
+        threadPool.shutdown();
+
+
+        StringBuffer result = new StringBuffer();
+        result.append("Is sorted: " + checkSorted(testdata) + "\n");
+        return result.toString();
+    }
+
+    private void quickSort(AtomicIntegerArray a, int left, int right) {
+        if (left < right) {
+            int mid = partition (a, left, right);
+            if (mid <= QUICKSORT_THRESHOLD) {
+                futureList.add(threadPool.submit(new Thread(() -> insertSort(a))));
+            } else {
+                futureList.add(threadPool.submit(new Thread(() -> quickSort(a, left, mid-1))));
+                futureList.add(threadPool.submit(new Thread(() -> quickSort(a, mid, right))));
+            }
+        }
+    }
+
+    private void quickSort(AtomicIntegerArray a){
+        quickSort(a, 0, a.length()-1);
+    }
+
+    private static int partition (AtomicIntegerArray a, int left, int right) {
+        int pivot = a.get((left + right) / 2);
+        while (left <= right) {
+            while (a.get(left) < pivot) {
+                left++;
+            }
+            while (a.get(right) > pivot) {
+                right--;
+            }
+            if (left <= right) {
+                int temp = a.get(left);
+                a.set(left, a.get(right));
+                a.set(right, temp);
+                left++;
+                right--;
+            }
+        }
+        return left;
+    }
+
+    private boolean checkSorted(AtomicIntegerArray a) {
+        for (int i=1; i < a.length(); i++) {
+            if (a.get(i-1) > a.get(i)) return false;
+        }
+        return true;
+    }
+
+    private void insertSort(AtomicIntegerArray a) {
+        for (int k = 1; k < a.length(); k++)
+            if (a.get(k) < a.get(k-1)){
+                int x = a.get(k);
+                int i;
+                for (i = k; ((i > 0) && (a.get(i-1) > x));i--)
+                    a.set(i, a.get(i-1));
+                a.set(i, x);
+            }
+    }
+}
+
diff --git a/12/src/test/java/ch/zhaw/ads/ThreadQuickerSortServerTest.java b/12/src/test/java/ch/zhaw/ads/ThreadQuickerSortServerTest.java
new file mode 100644
index 0000000..25f27a1
--- /dev/null
+++ b/12/src/test/java/ch/zhaw/ads/ThreadQuickerSortServerTest.java
@@ -0,0 +1,19 @@
+package ch.zhaw.ads;
+
+import org.junit.Test;
+import org.junit.Before;
+import static org.junit.Assert.*;
+import java.util.*;
+import java.io.*;
+
+public class ThreadQuickerSortServerTest {
+
+    ThreadQuickerSortServer serverToTest;
+
+    @Test
+    public void test1() {
+        serverToTest = new ThreadQuickerSortServer();
+        System.out.println(serverToTest.execute(""));
+    }
+}
+