diff --git a/src/main/java/com/thealgorithms/sorts/PancakeSort.java b/src/main/java/com/thealgorithms/sorts/PancakeSort.java index cd3e89307238..6079672a1d77 100644 --- a/src/main/java/com/thealgorithms/sorts/PancakeSort.java +++ b/src/main/java/com/thealgorithms/sorts/PancakeSort.java @@ -10,56 +10,35 @@ public class PancakeSort implements SortAlgorithm { @Override public > 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 the type of elements in the array + * @return the index of the maximum element + */ + private > 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; } } diff --git a/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java b/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java index 8d26532a1acd..0039bdfb03e7 100644 --- a/src/test/java/com/thealgorithms/sorts/PancakeSortTest.java +++ b/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(); } }