feat: add contains() method to DynamicArray

src/main/java/com/thealgorithms/datastructures/dynamicarray/DynamicArray.java

@@ -126,6 +126,21 @@ public int getSize() {
     public boolean isEmpty() {
         return size == 0;
     }
+    /**
+ * Checks whether the array contains the specified element.
+ *
+ *  @param element the element to check for
+ *  @return true if the array contains the specified element, false otherwise
+ */
+    public boolean contains(final E element) {
+        for (int i = 0; i < size; i++) {
+          if (Objects.equals(elements[i], element)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 
     /**
      * Returns a sequential stream with this collection as its source.

src/test/java/com/thealgorithms/datastructures/dynamicarray/DynamicArrayTest.java

@@ -255,4 +255,23 @@ public void testCapacityDoubling() {
         assertEquals(3, array.getSize());
         assertEquals("Charlie", array.get(2));
     }
+    @Test
+    public void testContains() {
+        DynamicArray<Integer> array = new DynamicArray<>();
+        array.add(1);
+        array.add(2);
+        array.add(3);
+
+        assertTrue(array.contains(2));
+        assertFalse(array.contains(5));
+    }
+
+@Test
+public void testContainsWithNull() {
+    DynamicArray<String> array = new DynamicArray<>();
+    array.add(null);
+
+    assertTrue(array.contains(null));
+}
+
 }