refactor: cleanup PancakeSort (TheAlgorithms#5295)

* refactor: PancakeSort cleanup, changing test to standard

* checkstyle: fix formatting

---------

Co-authored-by: alxklm <alx@alx.com>

Author: alxkm

src/main/java/com/thealgorithms/sorts/PancakeSort.java

@@ -10,56 +10,35 @@ public class PancakeSort implements SortAlgorithm {
 
     @Override
     public <T extends Comparable<T>> T[] sort(T[] array) {
-        int size = array.length;
+        if (array.length < 2) {
+            return array;
+        }
 
-        for (int i = 0; i < size; i++) {
-            T max = array[0];
-            int index = 0;
-            for (int j = 0; j < size - i; j++) {
-                if (SortUtils.less(max, array[j])) {
-                    max = array[j];
-                    index = j;
-                }
-            }
-            SortUtils.flip(array, index, array.length - 1 - i);
+        for (int currentSize = 0; currentSize < array.length; currentSize++) {
+            int maxIndex = findMaxIndex(array, currentSize);
+            SortUtils.flip(array, maxIndex, array.length - 1 - currentSize);
         }
+
         return array;
     }
 
-    public static void main(String[] args) {
-        Integer[] arr = {
-            10,
-            9,
-            8,
-            7,
-            6,
-            15,
-            14,
-            7,
-            4,
-            3,
-            8,
-            6,
-            3,
-            1,
-            2,
-            -2,
-            -5,
-            -8,
-            -3,
-            -1,
-            13,
-            12,
-            11,
-            5,
-            4,
-            3,
-            2,
-            1,
-        };
-        PancakeSort pancakeSort = new PancakeSort();
-        System.out.println("After sorting:");
-        pancakeSort.sort(arr);
-        SortUtils.print(arr);
+    /**
+     * Finds the index of the maximum element in the array up to the given size.
+     *
+     * @param array      the array to be searched
+     * @param currentSize the current size of the unsorted portion of the array
+     * @param <T>        the type of elements in the array
+     * @return the index of the maximum element
+     */
+    private <T extends Comparable<T>> int findMaxIndex(T[] array, int currentSize) {
+        T max = array[0];
+        int maxIndex = 0;
+        for (int i = 0; i < array.length - currentSize; i++) {
+            if (SortUtils.less(max, array[i])) {
+                max = array[i];
+                maxIndex = i;
+            }
+        }
+        return maxIndex;
     }
 }

src/test/java/com/thealgorithms/sorts/PancakeSortTest.java

@@ -1,80 +1,8 @@
 package com.thealgorithms.sorts;
 
-import static org.assertj.core.api.Assertions.assertThat;
-
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-
-public class PancakeSortTest {
-
-    private PancakeSort pancakeSort = new PancakeSort();
-
-    @Test
-    @DisplayName("Empty Array pancakeSort")
-    public void pancakeSortEmptyArray() {
-        Integer[] inputArray = {};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEmpty();
-    }
-
-    @Test
-    @DisplayName("PancakeSort single Integer Array")
-    public void pancakeSort() {
-        Integer[] inputArray = {2};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(inputArray);
-    }
-
-    @Test
-    @DisplayName("PancakeSort non duplicate Integer Array")
-    public void pancakeSortNonDuplicateIntegerArray() {
-        Integer[] inputArray = {2, 1, 77, 34, 14, 56, 8};
-        Integer[] expectedOutput = {1, 2, 8, 14, 34, 56, 77};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort Integer Array with duplicates")
-    public void pancakeSortDuplicateIntegerArray() {
-        Integer[] inputArray = {2, 1, 77, 34, 14, 77, 56, 14, 8};
-        Integer[] expectedOutput = {1, 2, 8, 14, 14, 34, 56, 77, 77};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort negative Integer Array with duplicates")
-    public void pancakeSortNegativeDuplicateIntegerArray() {
-        Integer[] inputArray = {2, 1, 77, -34, -14, 77, 56, -14, 8};
-        Integer[] expectedOutput = {-34, -14, -14, 1, 2, 8, 56, 77, 77};
-        Integer[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort single String Array")
-    public void pancakeSortSingleStringArray() {
-        String[] inputArray = {"W"};
-        String[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(inputArray);
-    }
-
-    @Test
-    @DisplayName("PancakeSort non duplicate String Array")
-    public void pancakeSortNonDuplicateStringArray() {
-        String[] inputArray = {"W", "A", "d", "be", "jk", "hb", "bgh"};
-        String[] expectedOutput = {"A", "W", "be", "bgh", "d", "hb", "jk"};
-        String[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
-    }
-
-    @Test
-    @DisplayName("PancakeSort String Array with duplicates")
-    public void pancakeSortDuplicateStringArray() {
-        String[] inputArray = {"W", "A", "d", "be", "jk", "hb", "bgh", "bgh", "W"};
-        String[] expectedOutput = {"A", "W", "W", "be", "bgh", "bgh", "d", "hb", "jk"};
-        String[] outputArray = pancakeSort.sort(inputArray);
-        assertThat(outputArray).isEqualTo(expectedOutput);
+public class PancakeSortTest extends SortingAlgorithmTest {
+    @Override
+    SortAlgorithm getSortAlgorithm() {
+        return new PancakeSort();
     }
 }