implement intPartitions method in MainExercises

src/main/java/MainExercises.java

@@ -8,28 +8,23 @@ public class MainExercises
         
         for (int i = 0; i < n; i++)
         {
-            char[] line = new char[i+1];
-
-            if (i == n-1 || i == 0)
+            result[i] = new char[i+1];
+            if (i == n-1)
             {
                 for (int j = 0; j <= i; j++)
                 {
-                    line[j] = '*';
+                    result[i][j] = '*';
                 }
             }
             else 
             {
-                line[0] = '*';
-                line[i] = '*';
+                result[i][0] = '*';
+                result[i][i] = '*';
 
-                for (int j = i - 1; j > 0; j--) {
-                    line[j] = ' ';
+                for (int j = 1; j < i; j++) result[i][j] = ' ';
             }
         }
 
-            result[i] = line;
-        }
-
         return result;
     }
 
@@ -69,37 +64,61 @@ public class MainExercises
     }
 
     public int[][] intPartitions(int n) {
-        ArrayList<int[]> result = new ArrayList<>();
-        ArrayList<Integer> curPartition = new ArrayList<>();
+        int[][] result;
+        ArrayList<ArrayList<Integer>> mainArray = new ArrayList<>();
 
-        fillPartition(n, n, curPartition, result);
+        ArrayList<Integer> start = new ArrayList<>();
+        start.add(n);
+        mainArray.add(start);
         
-        return result.toArray(new int[result.size()][]);
+        while (true) { 
+            ArrayList<Integer> latestArray = mainArray.get(mainArray.size() - 1);
+
+            Integer numberOfInterest = 0;
+            for (Integer number : latestArray)
+            {
+                if (number > 1) {
+                    numberOfInterest = number;
+                    break;
+                }
             }   
 
-    private void fillPartition(int max, int remaining, ArrayList<Integer> curPartition, ArrayList<int[]> result) {
-        if (remaining == 0) {
-            int size = curPartition.size();
-            int[] savingArr = new int[size];
+            if (numberOfInterest == 0) break;
 
-            for (int i = 0; i < size; i++) {
-                savingArr[i] = curPartition.get(i);
+            numberOfInterest--;
+            Integer remain = n - numberOfInterest;
+            ArrayList<Integer> newArray = new ArrayList<>();
+            newArray.add(numberOfInterest);
+
+            for (Integer number = numberOfInterest;;) {
+                if (number >= remain) {
+                    newArray.add(remain);
+                    break;
+                }
+                else {
+                    newArray.add(number);
+                    remain -= number;
+                }
             }
 
-            result.add(savingArr);
-            return;
+            mainArray.add(newArray);
         }
 
-        for (int i = Math.min(max, remaining); i >= 1; i--) {
-            curPartition.add(i);
-            int newRemaining = remaining - i;
+        result = new int[mainArray.size()][];
 
-            fillPartition(i, newRemaining, curPartition, result);
+        for (int i = 0; i < mainArray.size(); i++) {
+            ArrayList<Integer> array = mainArray.get(i);
 
-            curPartition.removeLast();
+            result[i] = new int[array.size()];
+
+            for (int j = 0; j < array.size(); j++) {
+                result[i][j] = array.get(j);
             }
         }
 
+        return result;
+    }
+
 
     public static void main()
     {