feat: Add RandomSearch new algorithm with Junit tests (#5701)

src/main/java/com/thealgorithms/searches/RandomSearch.java

@@ -0,0 +1,45 @@
+package com.thealgorithms.searches;
+
+import com.thealgorithms.devutils.searches.SearchAlgorithm;
+import java.util.HashSet;
+import java.util.Random;
+import java.util.Set;
+
+/**
+ * A Random Search algorithm that randomly selects an index and checks if the
+ * value at that index matches the target. It repeats the process until it
+ * finds the target or checks all elements.
+ *
+ * <p>
+ * Time Complexity: O(n) in the worst case.
+ * </p>
+ *
+ * @author Hardvan
+ */
+public class RandomSearch implements SearchAlgorithm {
+
+    private final Random random = new Random();
+
+    /**
+     * Finds the index of a given element using random search.
+     *
+     * @param array Array to search through
+     * @param key Element to search for
+     * @return Index of the element if found, -1 otherwise
+     */
+    @Override
+    public <T extends Comparable<T>> int find(T[] array, T key) {
+        Set<Integer> visitedIndices = new HashSet<>();
+        int size = array.length;
+
+        while (visitedIndices.size() < size) {
+            int randomIndex = random.nextInt(size);
+            if (array[randomIndex].compareTo(key) == 0) {
+                return randomIndex;
+            }
+            visitedIndices.add(randomIndex);
+        }
+
+        return -1;
+    }
+}

src/test/java/com/thealgorithms/searches/RandomSearchTest.java

@@ -0,0 +1,87 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class RandomSearchTest {
+
+    private RandomSearch randomSearch;
+
+    @BeforeEach
+    void setUp() {
+        randomSearch = new RandomSearch();
+    }
+
+    @Test
+    void testElementFound() {
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertNotEquals(-1, index, "Element should be found in the array.");
+        assertEquals(key, array[index], "Element found should match the key.");
+    }
+
+    @Test
+    void testElementNotFound() {
+        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        Integer key = 11;
+        int index = randomSearch.find(array, key);
+
+        assertEquals(-1, index, "Element not present in the array should return -1.");
+    }
+
+    @Test
+    void testEmptyArray() {
+        Integer[] emptyArray = {};
+        Integer key = 5;
+        int index = randomSearch.find(emptyArray, key);
+
+        assertEquals(-1, index, "Searching in an empty array should return -1.");
+    }
+
+    @Test
+    void testSingleElementArrayFound() {
+        Integer[] array = {5};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertEquals(0, index, "The key should be found at index 0 in a single-element array.");
+    }
+
+    @Test
+    void testSingleElementArrayNotFound() {
+        Integer[] array = {1};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertEquals(-1, index, "The key should not be found in a single-element array if it does not match.");
+    }
+
+    @Test
+    void testDuplicateElementsFound() {
+        Integer[] array = {1, 2, 3, 4, 5, 5, 5, 7, 8, 9, 10};
+        Integer key = 5;
+        int index = randomSearch.find(array, key);
+
+        assertNotEquals(-1, index, "The key should be found in the array with duplicates.");
+        assertEquals(key, array[index], "The key found should be 5.");
+    }
+
+    @Test
+    void testLargeArray() {
+        Integer[] largeArray = new Integer[1000];
+        for (int i = 0; i < largeArray.length; i++) {
+            largeArray[i] = i + 1; // Fill with values 1 to 1000
+        }
+
+        Integer key = 500;
+        int index = randomSearch.find(largeArray, key);
+
+        assertNotEquals(-1, index, "The key should be found in the large array.");
+        assertEquals(key, largeArray[index], "The key found should match 500.");
+    }
+}