Added test

Author: javadev

src/test/java/g3501_3600/s3509_maximum_product_of_subsequences_with_an_alternating_sum_equal_to_k/SolutionTest.java

@@ -20,4 +20,9 @@ void maxProduct2() {
     void maxProduct3() {
         assertThat(new Solution().maxProduct(new int[] {2, 2, 3, 3}, 0, 9), equalTo(9));
     }
+
+    @Test
+    void maxProduct4() {
+        assertThat(new Solution().maxProduct(new int[] {12, 0, 9}, 21, 20), equalTo(0));
+    }
 }