Implement intPartitions method

src/main/java/BonusExercises.java

@@ -65,11 +65,41 @@ public class BonusExercises {
         note: your implementation should be case-insensitive, e.g. Aba -> is palindrome
      */
     public List<String> findPalindromes(String string) {
-        List<String> list = new ArrayList<>();
-        // todo
-        return list;
+        List<String> result = new ArrayList<>();
+        String[] words = string.split("\\s+");
+        for (int i = 0; i < words.length; i++) {
+
+            String word = words[i];
+            word = word.replaceAll("[^a-zA-Z]", "");
+
+            if (word.length() < 3) {
+                continue;
             }
 
+            String lower = word.toLowerCase();
+            int left = 0;
+            int right = lower.length() - 1;
+
+            boolean isPalindrome = true;
+            while (left < right) {
+
+                if (lower.charAt(left) != lower.charAt(right)) {
+                    isPalindrome = false;
+                    break;
+                }
+                left++;
+                right--;
+            }
+
+            if (isPalindrome) {
+                result.add(word);
+            }
+        }
+
+        return result;
+    }
+
+
     public static void main(String[] args) {
         // you can test your code here
     }

src/main/java/MainExercises.java

@@ -1,5 +1,6 @@
-public class MainExercises
-{
+import javax.xml.transform.Result;
+
+public class MainExercises {
     /*
     you should create a triangle with "*" and return a two-dimensional array of characters based on that
     the triangle's area is empty, which means some characters should be " "
@@ -18,13 +19,29 @@ public class MainExercises
 
     the output has to be a two-dimensional array of characters, so don't just print the triangle!
  */
-    public char[][] generateTriangle(int n) {
+    public static char[][] generateTriangle(int n) {
 
-        // todo
-        return null;
+        char[][] triangle = new char[n][n];
 
+        int i = 0;
+        while (i < n) {
+            int j = 0;
+
+            while (j < n) {
+                if (j == 0 || j == i || i == n - 1) {
+                    triangle[i][j] = '*';
+                } else {
+                    triangle[i][j] = ' ';
                 }
 
+                j = j + 1;
+            }
+
+            i = i + 1;
+        }
+
+        return triangle;
+    }
 
 
     /*
@@ -58,8 +75,49 @@ public class MainExercises
            - Number of columns: matrix[0].length (if rectangular)
    */
     public int[] spiralTraversal(int[][] matrix) {
-        // todo
-        return null;
+        int rows = matrix.length;
+        int cols = matrix[0].length;
+
+        int[] result = new int[rows * cols];
+        int index = 0;
+
+        int top = 0;
+        int bottom = rows - 1;
+        int left = 0;
+        int right = cols - 1;
+
+        while (top <= bottom && left <= right) {
+
+            // left → right
+            for (int j = left; j <= right; j++) {
+                result[index++] = matrix[top][j];
+            }
+            top++;
+
+            // top → bottom
+            for (int i = top; i <= bottom; i++) {
+                result[index++] = matrix[i][right];
+            }
+            right--;
+
+            // right → left
+            if (top <= bottom) {
+                for (int j = right; j >= left; j--) {
+                    result[index++] = matrix[bottom][j];
+                }
+                bottom--;
+            }
+
+            // bottom → top
+            if (left <= right) {
+                for (int i = bottom; i >= top; i--) {
+                    result[index++] = matrix[i][left];
+                }
+                left++;
+            }
+        }
+
+        return result;
     }
 
     /*
@@ -89,15 +147,30 @@ public class MainExercises
         If you're familiar with Lists and ArrayLists, you can also edit the method's
         body to use them instead of arrays.
     */
-
         public int[][] intPartitions(int n) {
-        // todo
-        return null;
+
+            java.util.ArrayList<int[]> result = new java.util.ArrayList<>();
+            generate(n, n, new java.util.ArrayList<Integer>(), result);
+            return result.toArray(new int[result.size()][]);
+        }
+    private void generate(int remaining, int maxValue,
+                          java.util.ArrayList<Integer> current,
+                          java.util.ArrayList<int[]> result) {
+
+        if (remaining == 0) {
+            int[] arr = new int[current.size()];
+            for (int i = 0; i < current.size(); i++) {
+                arr[i] = current.get(i);
             }
 
+            result.add(arr);
+            return;
+        }
 
-    public static void main()
-    {
-
+        for (int i = Math.min(remaining, maxValue); i >= 1; i--) {
+            current.add(i);
+            generate(remaining - i, i, current, result);
+            current.remove(current.size() - 1);
+        }
     }
 }