Add tests SumOfSubset (#5021)

* Updated main and test

* removed

* style: reorder test cases

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

src/main/java/com/thealgorithms/dynamicprogramming/SumOfSubset.java

@@ -0,0 +1,18 @@
+package com.thealgorithms.dynamicprogramming;
+
+public class SumOfSubset {
+
+    public static boolean subsetSum(int[] arr, int num, int Key) {
+        if (Key == 0) {
+            return true;
+        }
+        if (num < 0 || Key < 0) {
+            return false;
+        }
+
+        boolean include = subsetSum(arr, num - 1, Key - arr[num]);
+        boolean exclude = subsetSum(arr, num - 1, Key);
+
+        return include || exclude;
+    }
+}