Solve Issue #326 comb sort algorithm

src/main/java/com/williamfiset/algorithms/sorting/CombSort.java

@@ -0,0 +1,69 @@
+package com.williamfiset.algorithms.sorting;
+
+import java.util.Scanner;
+
+public class CombSort
+{
+
+    // Function to sort list using Comb Sort
+    public void combsort(int sortlist[],int gapnumber)
+    {
+        int n = sortlist.length;
+
+        // initialize gap to length of the list
+        int gap = n;
+
+        // Initialize swapflag
+        int swapflag = 1;
+
+        // Keep running while gap is more than 1 and last
+        // iteration caused a swap
+        while (gap != 1 || swapflag == 1)
+        {
+            // Find next gap
+            // To find gap between elements
+             gap = (gap)/gapnumber;
+             if (gap < 1){
+                 gap=1;
+             }
+             System.out.println(gap);
+            // Initialize swapflag
+            swapflag = 0;
+
+            // Compare all elements with current gap
+            for (int i=0; i<n-gap; i++)
+            {
+                if (sortlist[i] > sortlist[i+gap])
+                {
+                    int temp = sortlist[i];
+                    sortlist[i] = sortlist[i+gap];
+                    sortlist[i+gap] = temp;
+                    // Set swapped
+                    swapflag = 1;
+                }
+            }
+        }
+    }
+
+    /**main method, allow users enter number the want to sort, and then scan the number into a int list,
+     * the program will use comb sort to sort the int list and print it out for users
+    */
+    public static void main(String args[])
+    {
+        CombSort combSort = new CombSort();
+        Scanner scan = new Scanner(System.in);
+        System.out.println("Enter number of the numbers you want to sort");
+        int n = scan.nextInt();
+        System.out.println("Enter number of gap you want to use in the sort");
+        int n1 = scan.nextInt();
+        System.out.println("Enter the numbers:");
+        int[] arr = new int[n];
+        for (int i=0;i<n;i++)
+            arr[i]=scan.nextInt();
+        combSort.combsort(arr,n1);
+        System.out.println("sorted array");
+        for (int i=0; i<arr.length; ++i)
+            System.out.print(arr[i] + " ");
+
+    }
+}

src/test/java/com/williamfiset/algorithms/sorting/CombSortTest.java

@@ -0,0 +1,50 @@
+package com.williamfiset.algorithms.sorting;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import static com.google.common.truth.Truth.assertThat;
+
+public class CombSortTest {
+    static Random random = new Random();
+
+    CombSort combSort = new CombSort();
+
+    @Test
+    public void randomCombSort_smallNumbers() {
+        for (int size = 0; size < 1000; size++) {
+            int[] values = new int[size];
+            for (int i = 0; i < size; i++) {
+                values[i] = randInt(1, 50);
+            }
+            int[] copy = values.clone();
+
+            Arrays.sort(values);
+            combSort.combsort(copy,2);
+            assertThat(values).isEqualTo(copy);
+        }
+    }
+
+    @Test
+    public void randomRadixSort_largeNumbers() {
+        for (int size = 0; size < 1000; size++) {
+            int[] values = new int[size];
+            for (int i = 0; i < size; i++) {
+                values[i] = randInt(1, Integer.MAX_VALUE);
+            }
+            int[] copy = values.clone();
+
+            Arrays.sort(values);
+            combSort.combsort(copy,2);
+
+            assertThat(values).isEqualTo(copy);
+        }
+    }
+
+    // return a random number between [min, max]
+    static int randInt(int min, int max) {
+        return random.nextInt((max - min) + 1) + min;
+    }
+}