refactor: refactor insertion sort

Author: codejsha

java-algorithm/src/main/java/com/example/algorithm/sort/InsertionSort.java

@@ -1,29 +1,15 @@
 package com.example.algorithm.sort;
 
 public class InsertionSort {
-    public static int[] insertionSort(int[] array) {
-        for (var i = 1; i < array.length; i++) {
-            var key = array[i];
-            var j = i - 1;
-            while ((j > -1) && (array[j] > key)) {
+    public static <T extends Comparable<T>> void insertionSort(T[] array) {
+        for (int i = 1; i < array.length; i++) {
+            T key = array[i];
+            int j = i - 1;
+            while ((j > -1) && (array[j].compareTo(key) > 0)) {
                 array[j + 1] = array[j];
                 j--;
             }
             array[j + 1] = key;
         }
-        return array;
-    }
-
-    public static Double[] insertionSort(Double[] array) {
-        for (var i = 1; i < array.length; i++) {
-            var key = array[i];
-            var j = i - 1;
-            while ((j > -1) && (array[j] > key)) {
-                array[j + 1] = array[j];
-                j--;
-            }
-            array[j + 1] = key;
-        }
-        return array;
     }
 }

java-algorithm/src/test/java/com/example/algorithm/sort/InsertionSortTest.java

@@ -1,27 +1,27 @@
 package com.example.algorithm.sort;
 
 import org.junit.jupiter.api.AfterEach;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
 class InsertionSortTest {
-    int[] array;
-
-    @BeforeEach
-    void setUp() {
-        array = new int[]{64, 32, 16, 8, 4};
-    }
-
     @AfterEach
     void tearDown() {
         System.gc();
     }
 
     @Test
     void testInsertionSort() {
-        var result = InsertionSort.insertionSort(array);
-        assertArrayEquals(new int[]{4, 8, 16, 32, 64}, result);
+        var array = new Integer[]{64, 32, 16, 8, 4};
+        InsertionSort.insertionSort(array);
+        assertArrayEquals(new Integer[]{4, 8, 16, 32, 64}, array);
+    }
+
+    @Test
+    void testInsertionSort2() {
+        var array = new Double[]{64.5, 32.5, 16.5, 8.5, 4.5};
+        InsertionSort.insertionSort(array);
+        assertArrayEquals(new Double[]{4.5, 8.5, 16.5, 32.5, 64.5}, array);
     }
 }