From 92e737280384c6a85155d6db7864a95920571cc3 Mon Sep 17 00:00:00 2001
From: Italo Batista <italo.batista@ccc.ufcg.edu.br>
Date: Tue, 31 Oct 2017 00:26:53 -0300
Subject: [PATCH] Add sorting algo. QuickSortMedianOfThree

---
 Sorts/QuickSortMedianOfThree.java | 88 +++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 Sorts/QuickSortMedianOfThree.java

diff --git a/Sorts/QuickSortMedianOfThree.java b/Sorts/QuickSortMedianOfThree.java
new file mode 100644
index 000000000000..3cc0c99c023d
--- /dev/null
+++ b/Sorts/QuickSortMedianOfThree.java
@@ -0,0 +1,88 @@
+
+public class QuickSortMedianOfThree {
+
+    public void sort(int[] array, int leftIndex, int rightIndex){
+
+        if (leftIndex < rightIndex) {
+
+            medianOfThree(array, leftIndex, rightIndex);
+            changePivot(array, leftIndex, rightIndex);
+
+            int pivotIndex = partition(array, leftIndex, rightIndex);
+
+            sort(array, leftIndex, pivotIndex - 1);
+            sort(array, pivotIndex + 1, rightIndex);
+
+        }
+    }
+
+    private void medianOfThree(int[] array, int leftIndex, int rightIndex){
+
+        int shortter = leftIndex;
+        int mid = leftIndex + (rightIndex - leftIndex) / 2;
+        int bigger = rightIndex;
+
+        if (array[mid] < array[shortter]) {
+            swap(array, shortter, mid);
+        }
+        if (array[bigger] < array[shortter]) {
+            swap(array, shortter, bigger);
+        }
+        if (array[bigger] < array[mid]) {
+            swap(array, bigger, mid);
+        }
+
+    }
+
+    private void changePivot(int[] array, int leftIndex, int rightIndex) {
+        int pivotIndex = leftIndex + (rightIndex - leftIndex) / 2;
+        if (rightIndex - leftIndex >= 1) {
+            swap(array, pivotIndex, rightIndex - 1);
+        }
+
+    }
+
+    private int partition(int[] array, int leftIndex, int rightIndex) {
+
+        int i = leftIndex;
+        int j = leftIndex + 1;
+        int p = leftIndex;
+
+        while (j <= rightIndex) {
+
+            if (array[j] < array[p]) {
+                i = i + 1;
+                swap(array, i, j);
+            }
+            j = j + 1;
+        }
+
+        swap(array, i, p);
+        return i;
+    }
+
+    private void swap(int[] array, int i, int j) {
+        if(array == null)
+            throw new IllegalArgumentException();
+
+        int temp = array[i];
+        array[i] = array[j];
+        array[j] = temp;
+    }
+
+    public static void main(String args[]) {
+
+        int[] array = new int[] {6, 41, 32, 7, 26, 4, 37, 49, 11, 18, 36};
+        int leftIndex = 0;
+        int rightIdex = array.length - 1;
+
+        QuickSortMedianOfThree quick = new QuickSortMedianOfThree();
+        quick.sort(array, leftIndex, rightIdex);
+
+        System.out.println("The sorted array is:");
+        for (int i=0; i < array.length; i++)
+            System.out.print(array[i] + " ");
+
+    }
+
+}