style: make SubsetCount a proper utility (#5153)

spotbugs-exclude.xml

@@ -74,9 +74,6 @@
     <Match>
         <Bug pattern="DM_BOXED_PRIMITIVE_FOR_PARSING" />
     </Match>
-    <Match>
-        <Bug pattern="MS_SHOULD_BE_FINAL" />
-    </Match>
     <Match>
         <Bug pattern="UWF_UNWRITTEN_FIELD" />
     </Match>

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

@@ -6,7 +6,9 @@ package com.thealgorithms.dynamicprogramming;
  * StackOverflow(https://stackoverflow.com/questions/22891076/count-number-of-subsets-with-sum-equal-to-k)
  * @author Samrat Podder(https://github.com/samratpodder)
  */
-public class SubsetCount {
+public final class SubsetCount {
+    private SubsetCount() {
+    }
 
     /**
      * Dynamic Programming Implementation.
@@ -16,7 +18,7 @@ public class SubsetCount {
      * @param target is the sum of each element of the subset taken together
      *
      */
-    public int getCount(int[] arr, int target) {
+    public static int getCount(int[] arr, int target) {
         /**
          * Base Cases - If target becomes zero, we have reached the required sum for the subset
          * If we reach the end of the array arr then, either if target==arr[end], then we add one to
@@ -46,7 +48,7 @@ public class SubsetCount {
      * @param arr is the input array on which subsets are  to searched
      * @param target is the sum of each element of the subset taken together
      */
-    public int getCountSO(int[] arr, int target) {
+    public static int getCountSO(int[] arr, int target) {
         int n = arr.length;
         int[] prev = new int[target + 1];
         prev[0] = 1;

src/test/java/com/thealgorithms/dynamicprogramming/SubsetCountTest.java

@@ -5,27 +5,25 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import org.junit.jupiter.api.Test;
 
 public class SubsetCountTest {
-    public static SubsetCount obj = new SubsetCount();
-
     @Test
     void hasMultipleSubset() {
         int[] arr = new int[] {1, 2, 3, 3};
-        assertEquals(3, obj.getCount(arr, 6));
+        assertEquals(3, SubsetCount.getCount(arr, 6));
     }
     @Test
     void singleElementSubset() {
         int[] arr = new int[] {1, 1, 1, 1};
-        assertEquals(4, obj.getCount(arr, 1));
+        assertEquals(4, SubsetCount.getCount(arr, 1));
     }
 
     @Test
     void hasMultipleSubsetSO() {
         int[] arr = new int[] {1, 2, 3, 3};
-        assertEquals(3, obj.getCountSO(arr, 6));
+        assertEquals(3, SubsetCount.getCountSO(arr, 6));
     }
     @Test
     void singleSubsetSO() {
         int[] arr = new int[] {1, 1, 1, 1};
-        assertEquals(1, obj.getCountSO(arr, 4));
+        assertEquals(1, SubsetCount.getCountSO(arr, 4));
     }
 }