Add Circle Sort (#2696)

Sorts/CircleSort.java

@@ -0,0 +1,68 @@
+package Sorts;
+
+import static Sorts.SortUtils.*;
+
+public class CircleSort implements SortAlgorithm {
+    /* This method implements the circle sort
+    * @param array The array to be sorted 
+    */
+    @Override
+    public <T extends Comparable<T>> T[] sort(T[] array) {
+        int n = array.length;
+        while(doSort(array, 0, n - 1));
+        return array;
+    }
+    
+    /* This method implements the cyclic sort recursive version
+    * @param array The array to be sorted
+    * @param the left boundary of the part currently being sorted
+    * @param the right boundary of the part currently being sorted
+    */
+    private <T extends Comparable<T>> Boolean doSort(T[] array, int left, int right) {
+        Boolean swapped = false;
+        
+        if (left == right) {
+            return false;
+        }
+        
+        int low = left;
+        int high = right;
+        
+        while (low < high) {
+            if (array[low].compareTo(array[high]) > 0) {
+                swap(array, low, high);
+                swapped = true;
+            }
+            low++;
+            high--;
+        }
+        
+        if (low == high && array[low].compareTo(array[high + 1]) > 0) {
+            swap(array, low, high + 1);
+            swapped = true;
+        }
+        
+        int mid = left + (right - left)/2;
+        Boolean leftHalf = doSort(array, left, mid);
+        Boolean rightHalf = doSort(array, mid + 1, right);
+        
+        return swapped || leftHalf || rightHalf;
+    }
+    
+    /* Driver code*/
+    public static void main(String[] args) {
+        CircleSort CSort = new CircleSort();
+
+        Integer[] arr = {4, 23, 6, 78, 1, 54, 231, 9, 12};
+        CSort.sort(arr);
+        for (int i = 0; i < arr.length - 1; ++i) {
+        assert arr[i] <= arr[i + 1];
+        }
+
+        String[] stringArray = {"c", "a", "e", "b", "d"};
+        CSort.sort(stringArray);
+        for (int i = 0; i < stringArray.length - 1; ++i) {
+        assert arr[i].compareTo(arr[i + 1]) <= 0;
+        }
+    }
+}