Added algorithm class CycleSort and its corresponding test class CycleSortTest

ani03sha · Anirudh Sharma · commit 9763b6df89d0 · 2019-01-02T12:55:40.000+05:30
diff --git a/src/main/java/src/main/java/com/sorts/CycleSort.java b/src/main/java/src/main/java/com/sorts/CycleSort.java
@@ -0,0 +1,87 @@
+package src.main.java.com.sorts;
+
+public class CycleSort {
+
+    /**
+     * @param arr Array to be sorted
+     * @param <T> Generic type
+     * @return arr Sorted array
+     */
+    public <T extends Comparable<T>> T[] sort(T[] arr) {
+
+        int n = arr.length;
+
+        // Counter for the number of memory writes
+        int count = 0;
+
+        // Traverse array and put the elements on their respective right places
+        for (int i = 0; i < n - 2; i++) {
+
+            // Initialize item as the starting point
+            T item = arr[i];
+
+            // Find the position where we want to put the item
+            // Basically we count all the smaller elements to the right of the item
+            int position = i;
+
+            for (int j = i + 1; j < n; j++) {
+                if (arr[j].compareTo(item) < 0) {
+                    position++;
+                }
+            }
+
+            // Check if the element is already at the correct position...
+            if (position == i) {
+
+                // .. then we do not have to do anything
+                continue;
+            }
+
+            // Ignore duplicate elements
+            while (item == arr[position]) {
+                position++;
+            }
+
+            // Put the elements at its right position
+            if (position != i) {
+
+                // Swap
+                T temp = item;
+                item = arr[position];
+                arr[position] = temp;
+
+                count++;
+            }
+
+            // Rotate remaining cycle
+            while (position != i) {
+                position = i;
+
+                // Find the position where we put the element
+                for (int j = i + 1; j < n; j++) {
+                    if (arr[j].compareTo(item) < 0) {
+                        position++;
+                    }
+                }
+
+                // Ignore duplicate elements
+                while (item == arr[position]) {
+                    position++;
+                }
+
+                // Put the element to its correct position
+                if (item != arr[position]) {
+                    T temp = arr[position];
+                    arr[position] = item;
+                    item = temp;
+
+                    count++;
+                }
+            }
+        }
+
+        System.out.println("Number of memory writes :: " + count);
+
+        return arr;
+    }
+}
diff --git a/src/test/java/src/test/java/com/sorts/CycleSortTest.java b/src/test/java/src/test/java/com/sorts/CycleSortTest.java
@@ -0,0 +1,35 @@
+package src.test.java.com.sorts;
+
+import org.junit.Assert;
+import org.junit.Test;
+import src.main.java.com.sorts.CycleSort;
+
+public class CycleSortTest {
+
+    @Test
+    public void cycleSortIntegerTest() {
+
+        CycleSort cycleSort = new CycleSort();
+
+        // Test case for integers
+        Integer[] unsortedInt = new Integer[]{5, 1, 7, 0, 2, 9, 6, 3, 4, 8};
+        Integer[] sortedInt = new Integer[]{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+        Assert.assertArrayEquals(sortedInt, cycleSort.sort(unsortedInt));
+
+        // Test case for floating point numbers
+        Float[] unsortedFloat = new Float[]{6.7f, 21.1f, 0.9f, -3.2f, 5.9f, -21.3f};
+        Float[] sortedFloat = new Float[]{-21.3f, -3.2f, 0.9f, 5.9f, 6.7f, 21.1f};
+        Assert.assertArrayEquals(sortedFloat, cycleSort.sort(unsortedFloat));
+
+        // Test case for characters
+        Character[] unsortedChar = new Character[]{'c', 'a', 'b', 'A', 'C', 'B'};
+        Character[] sortedChar = new Character[]{'A', 'B', 'C', 'a', 'b', 'c'};
+        Assert.assertArrayEquals(sortedChar, cycleSort.sort(unsortedChar));
+
+        // Test case for Strings
+        String[] unsortedStr = new String[]{"Edward", "Linus", "David", "Alan", "Dennis", "Robert", "Ken"};
+        String[] sortedStr = new String[]{"Alan", "David", "Dennis", "Edward", "Ken", "Linus", "Robert"};
+        Assert.assertArrayEquals(sortedStr, cycleSort.sort(unsortedStr));
+
+    }
+}
