From 6d25796bac30c946da7055e9033f34ea6f815f83 Mon Sep 17 00:00:00 2001
From: Daniel Langbein <daniel@systemli.org>
Date: Tue, 17 Dec 2024 19:14:30 +0000
Subject: [PATCH] import QuickSort

---
 .../uni_marburg/powersort/sort/QuickSort.java | 40 +++++++++++++++++++
 .../uni_marburg/powersort/sort/SortEnum.java  |  2 +
 .../powersort/sort/QuickSortTest.java         |  7 ++++
 3 files changed, 49 insertions(+)
 create mode 100644 app/src/main/java/de/uni_marburg/powersort/sort/QuickSort.java
 create mode 100644 app/src/test/java/de/uni_marburg/powersort/sort/QuickSortTest.java

diff --git a/app/src/main/java/de/uni_marburg/powersort/sort/QuickSort.java b/app/src/main/java/de/uni_marburg/powersort/sort/QuickSort.java
new file mode 100644
index 0000000..815b8b7
--- /dev/null
+++ b/app/src/main/java/de/uni_marburg/powersort/sort/QuickSort.java
@@ -0,0 +1,40 @@
+package de.uni_marburg.powersort.sort;
+
+public class QuickSort {
+    /**
+     * Based on https://www.baeldung.com/java-quicksort
+     */
+    public static void sort(Integer[] arr) {
+        quickSort(arr, 0, arr.length-1);
+    }
+
+    private static void quickSort(Integer[] arr, int begin, int end) {
+        if (begin < end) {
+            int partitionIndex = partition(arr, begin, end);
+
+            quickSort(arr, begin, partitionIndex-1);
+            quickSort(arr, partitionIndex+1, end);
+        }
+    }
+
+    private static int partition(Integer[] arr, int begin, int end) {
+        int pivot = arr[end];
+        int i = (begin-1);
+
+        for (int j = begin; j < end; j++) {
+            if (arr[j] <= pivot) {
+                i++;
+
+                int swapTemp = arr[i];
+                arr[i] = arr[j];
+                arr[j] = swapTemp;
+            }
+        }
+
+        int swapTemp = arr[i+1];
+        arr[i+1] = arr[end];
+        arr[end] = swapTemp;
+
+        return i+1;
+    }
+}
diff --git a/app/src/main/java/de/uni_marburg/powersort/sort/SortEnum.java b/app/src/main/java/de/uni_marburg/powersort/sort/SortEnum.java
index 0ceb21a..06e346b 100644
--- a/app/src/main/java/de/uni_marburg/powersort/sort/SortEnum.java
+++ b/app/src/main/java/de/uni_marburg/powersort/sort/SortEnum.java
@@ -5,6 +5,7 @@ import de.uni_marburg.powersort.benchmark.NaturalOrder;
 
 public enum SortEnum {
     BUBBLE_SORT,
+    QUICK_SORT,
     MERGE_SORT,
     TIM_SORT,
     FINN_SORT,
@@ -13,6 +14,7 @@ public enum SortEnum {
     public SortImpl getSortImpl() {
         return switch (this) {
             case BUBBLE_SORT -> array -> BubbleSort.sort(array, NaturalOrder.INSTANCE);
+            case QUICK_SORT -> array -> QuickSort.sort((Integer[]) array); // TODO rm cast
             case MERGE_SORT -> array -> MergeSort.legacyMergeSort(array, NaturalOrder.INSTANCE);
             case TIM_SORT -> array -> TimSort.sort(array, 0, array.length, NaturalOrder.INSTANCE, null, 0, 0);
             case FINN_SORT -> array -> FinnSort.sort(array, NaturalOrder.INSTANCE);
diff --git a/app/src/test/java/de/uni_marburg/powersort/sort/QuickSortTest.java b/app/src/test/java/de/uni_marburg/powersort/sort/QuickSortTest.java
new file mode 100644
index 0000000..033fb04
--- /dev/null
+++ b/app/src/test/java/de/uni_marburg/powersort/sort/QuickSortTest.java
@@ -0,0 +1,7 @@
+package de.uni_marburg.powersort.sort;
+
+public class QuickSortTest extends AbstractSortTest {
+    QuickSortTest() {
+        sortAlg = SortEnum.ASORT;
+    }
+}