diff --git a/DIRECTORY.md b/DIRECTORY.md index ff6e29806847..a22863e8b052 100644 --- a/DIRECTORY.md +++ b/DIRECTORY.md @@ -1007,6 +1007,7 @@ * [InterpolationSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/InterpolationSearchTest.java) * [IterativeBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeBinarySearchTest.java) * [IterativeTernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/IterativeTernarySearchTest.java) + * [JumpSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/JumpSearchTest.java) * [KMPSearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/KMPSearchTest.java) * [OrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/OrderAgnosticBinarySearchTest.java) * [PerfectBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/PerfectBinarySearchTest.java) diff --git a/src/main/java/com/thealgorithms/searches/JumpSearch.java b/src/main/java/com/thealgorithms/searches/JumpSearch.java index f499cf8079cc..8dcec3a819a4 100644 --- a/src/main/java/com/thealgorithms/searches/JumpSearch.java +++ b/src/main/java/com/thealgorithms/searches/JumpSearch.java @@ -2,44 +2,55 @@ import com.thealgorithms.devutils.searches.SearchAlgorithm; +/** + * An implementation of the Jump Search algorithm. + * + *

+ * Jump Search is an algorithm for searching sorted arrays. It works by dividing the array + * into blocks of a fixed size (the block size is typically the square root of the array length) + * and jumping ahead by this block size to find a range where the target element may be located. + * Once the range is found, a linear search is performed within that block. + * + *

+ * The Jump Search algorithm is particularly effective for large sorted arrays where the cost of + * performing a linear search on the entire array would be prohibitive. + * + *

+ * Worst-case performance: O(√N)
+ * Best-case performance: O(1)
+ * Average performance: O(√N)
+ * Worst-case space complexity: O(1) + * + *

+ * This class implements the {@link SearchAlgorithm} interface, providing a generic search method + * for any comparable type. + */ public class JumpSearch implements SearchAlgorithm { - public static void main(String[] args) { - JumpSearch jumpSearch = new JumpSearch(); - Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; - for (int i = 0; i < array.length; i++) { - assert jumpSearch.find(array, i) == i; - } - assert jumpSearch.find(array, -1) == -1; - assert jumpSearch.find(array, 11) == -1; - } - /** - * Jump Search algorithm implements + * Jump Search algorithm implementation. * - * @param array the array contains elements - * @param key to be searched - * @return index of {@code key} if found, otherwise -1 + * @param array the sorted array containing elements + * @param key the element to be searched + * @return the index of {@code key} if found, otherwise -1 */ @Override public > int find(T[] array, T key) { int length = array.length; - /* length of array */ int blockSize = (int) Math.sqrt(length); - /* block size to be jumped */ int limit = blockSize; - while (key.compareTo(array[limit]) > 0 && limit < array.length - 1) { - limit = Math.min(limit + blockSize, array.length - 1); + // Jumping ahead to find the block where the key may be located + while (limit < length && key.compareTo(array[limit]) > 0) { + limit = Math.min(limit + blockSize, length - 1); } - for (int i = limit - blockSize; i <= limit; i++) { - if (array[i] == key) { - /* execute linear search */ + // Perform linear search within the identified block + for (int i = limit - blockSize; i <= limit && i < length; i++) { + if (array[i].equals(key)) { return i; } } return -1; - /* not found */ } } diff --git a/src/test/java/com/thealgorithms/searches/JumpSearchTest.java b/src/test/java/com/thealgorithms/searches/JumpSearchTest.java new file mode 100644 index 000000000000..3fa319b66a41 --- /dev/null +++ b/src/test/java/com/thealgorithms/searches/JumpSearchTest.java @@ -0,0 +1,94 @@ +package com.thealgorithms.searches; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import org.junit.jupiter.api.Test; + +/** + * Unit tests for the JumpSearch class. + */ +class JumpSearchTest { + + /** + * Test for finding an element present in the array. + */ + @Test + void testJumpSearchFound() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; + Integer key = 5; // Element to find + assertEquals(5, jumpSearch.find(array, key), "The index of the found element should be 5."); + } + + /** + * Test for finding the first element in the array. + */ + @Test + void testJumpSearchFirstElement() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; + Integer key = 0; // First element + assertEquals(0, jumpSearch.find(array, key), "The index of the first element should be 0."); + } + + /** + * Test for finding the last element in the array. + */ + @Test + void testJumpSearchLastElement() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; + Integer key = 10; // Last element + assertEquals(10, jumpSearch.find(array, key), "The index of the last element should be 10."); + } + + /** + * Test for finding an element not present in the array. + */ + @Test + void testJumpSearchNotFound() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; + Integer key = -1; // Element not in the array + assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in the array."); + } + + /** + * Test for finding an element in an empty array. + */ + @Test + void testJumpSearchEmptyArray() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = {}; // Empty array + Integer key = 1; // Key not present + assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in an empty array."); + } + + /** + * Test for finding an element in a large array. + */ + @Test + void testJumpSearchLargeArray() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = new Integer[1000]; + for (int i = 0; i < array.length; i++) { + array[i] = i * 2; // Fill the array with even numbers + } + Integer key = 256; // Present in the array + assertEquals(128, jumpSearch.find(array, key), "The index of the found element should be 128."); + } + + /** + * Test for finding an element in a large array when it is not present. + */ + @Test + void testJumpSearchLargeArrayNotFound() { + JumpSearch jumpSearch = new JumpSearch(); + Integer[] array = new Integer[1000]; + for (int i = 0; i < array.length; i++) { + array[i] = i * 2; // Fill the array with even numbers + } + Integer key = 999; // Key not present + assertEquals(-1, jumpSearch.find(array, key), "The element should not be found in the array."); + } +}