diff --git a/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java new file mode 100644 index 000000000000..8a02b30a9f0e --- /dev/null +++ b/src/main/java/com/thealgorithms/searches/RecursiveBinarySearch.java @@ -0,0 +1,74 @@ +// Code by Pronay Debnath +// Created:- 1/10/2023 +// File Name should be RecursiveBinarySearch.java +// Explanation:- https://www.tutorialspoint.com/java-program-for-binary-search-recursive + +import java.util.*; + +// Create a SearchAlgorithm class with a generic type +abstract class SearchAlgorithm> { + // Abstract find method to be implemented by subclasses + public abstract int find(T[] arr, T target); +} + +public class RecursiveBinarySearch> extends SearchAlgorithm { + + // Override the find method as required + @Override + public int find(T[] arr, T target) { + // Call the recursive binary search function + return binsear(arr, 0, arr.length - 1, target); + } + + // Recursive binary search function + public int binsear(T[] arr, int left, int right, T target) { + if (right >= left) { + int mid = left + (right - left) / 2; + + // Compare the element at the middle with the target + int comparison = arr[mid].compareTo(target); + + // If the element is equal to the target, return its index + if (comparison == 0) { + return mid; + } + + // If the element is greater than the target, search in the left subarray + if (comparison > 0) { + return binsear(arr, left, mid - 1, target); + } + + // Otherwise, search in the right subarray + return binsear(arr, mid + 1, right, target); + } + + // Element is not present in the array + return -1; + } + + public static void main(String[] args) { + Scanner sc = new Scanner(System.in); + // User inputs + System.out.print("Enter the number of elements in the array: "); + int n = sc.nextInt(); + + Integer[] a = new Integer[n]; // You can change the array type as needed + + System.out.println("Enter the elements in sorted order:"); + + for (int i = 0; i < n; i++) { + a[i] = sc.nextInt(); + } + + System.out.print("Enter the target element to search for: "); + int t = sc.nextInt(); + + RecursiveBinarySearch searcher = new RecursiveBinarySearch<>(); + int res = searcher.find(a, t); + + if (res == -1) + System.out.println("Element not found in the array."); + else + System.out.println("Element found at index " + res); + } +} diff --git a/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java new file mode 100644 index 000000000000..3b2cdead1c6b --- /dev/null +++ b/src/test/java/com/thealgorithms/searches/RecursiveBinarySearchTest.java @@ -0,0 +1,40 @@ +// Created by Pronay Debnath +// Date:- 1/10/2023 +// Test file updated with JUnit tests + +import static org.junit.jupiter.api.Assertions.*; + +import org.junit.jupiter.api.Test; // Import the JUnit 5 Test annotation + +public class RecursiveBinarySearchTest { + + @Test + public void testBinarySearch() { + // Create an instance of GenericBinarySearch + RecursiveBinarySearch searcher = new RecursiveBinarySearch<>(); + + // Test case 1: Element found in the array + Integer[] arr1 = {1, 2, 3, 4, 5}; + int target1 = 3; + int result1 = searcher.binsear(arr1, 0, arr1.length - 1, target1); + assertEquals(2, result1); + + // Test case 2: Element not found in the array + Integer[] arr2 = {1, 2, 3, 4, 5}; + int target2 = 6; + int result2 = searcher.binsear(arr2, 0, arr2.length - 1, target2); + assertEquals(-1, result2); + + // Test case 3: Element found at the beginning of the array + Integer[] arr3 = {10, 20, 30, 40, 50}; + int target3 = 10; + int result3 = searcher.binsear(arr3, 0, arr3.length - 1, target3); + assertEquals(0, result3); + + // Test case 4: Element found at the end of the array + Integer[] arr4 = {10, 20, 30, 40, 50}; + int target4 = 50; + int result4 = searcher.binsear(arr4, 0, arr4.length - 1, target4); + assertEquals(4, result4); + } +}