src/main/java/MainExercises.java

@@ -153,10 +153,25 @@ public class MainExercises
         body to use them instead of arrays.
     */
 
-    public static ArrayList<ArrayList<Integer>> intPartitions(int n) {
+    public static int[][] intPartitions(int n) {
         ArrayList<ArrayList<Integer>> result = new ArrayList<>();
         backtrack(n, n, new ArrayList<>(), result);
-        return result;
+
+        ArrayList<int[]> resLst = new ArrayList<int[]>();
+        for (int i = 0; i < result.size(); i++) {
+            int[] row = new int[result.get(i).size()];
+            for (int j = 0; j < result.get(i).size(); j++) {
+                row[j] = result.get(i).get(j);
+            }
+            resLst.add(row);
+        }
+
+        int[][] res = new int[resLst.size()][];
+        for (int k = 0; k < resLst.size(); k++) {
+            res[k] = resLst.get(k);
+        }
+
+        return res;
     }
 
     private static void backtrack(int remaining, int max,

src/test/java/MainTestPartitions.java

@@ -3,6 +3,7 @@ import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+
 public class MainTestPartitions {
     static MainExercises ex;
 
@@ -63,3 +64,5 @@ public class MainTestPartitions {
         assertArrayEquals(expected, ex.intPartitions(6));
     }
 }
+
+