src/main/java/MainExercises.java

@@ -1,3 +1,7 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
 public class MainExercises
 {
     /*
@@ -18,10 +22,37 @@ 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) {
 
         // todo
-        return null;
+        if (n <= 0)
+            return new char[0][0];
+
+       char[][] triangle = new char[n][n];
+        for (int i = 0 ; i< n ; i++)
+        {
+            if (i == n-1)
+            {
+                for (int j = 0 ; j < n ; j++)
+                {
+                    triangle[i][j] ='*';
+                }
+            }
+
+            else
+            {
+                for (int j = 0 ; j <= i ; j++) {
+                    if (j == 0 || j== i)
+                        triangle[i][j] = '*';
+
+                    else
+                        triangle[i][j] = ' ';
+                }
+            }
+        }
+
+        return triangle;
 
     }
 
@@ -59,7 +90,46 @@ public class MainExercises
    */
     public int[] spiralTraversal(int[][] matrix) {
         // todo
-        return null;
+        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
+            return new int[0];
+        }
+
+        int rows = matrix.length;
+        int cols = matrix[0].length;
+        int[] spiral = new int[rows * cols];
+
+        int top = 0;
+        int bottom = rows - 1;
+        int left = 0;
+        int right = cols - 1;
+        int index = 0;
+
+        while (top <= bottom && left <= right) {
+            for (int j = left; j <= right; j++) {
+                spiral[index++] = matrix[top][j];
+            }
+            top++;
+
+            for (int i = top; i <= bottom; i++) {
+                spiral[index++] = matrix[i][right];
+            }
+            right--;
+
+            if (top <= bottom) {
+                for (int j = right; j >= left; j--) {
+                    spiral[index++] = matrix[bottom][j];
+                }
+                bottom--;
+            }
+
+            if (left <= right) {
+                for (int i = bottom; i >= top; i--) {
+                    spiral[index++] = matrix[i][left];
+                }
+                left++;
+            }
+        }
+        return spiral;
     }
 
     /*
@@ -92,12 +162,76 @@ public class MainExercises
 
     public int[][] intPartitions(int n) {
         // todo
-        return null;
+        if (n <= 0) {
+            return new int[0][0];
+        }
+
+        List<int[]> partitionsList = new ArrayList<>();
+        generatePartitions(n, n, new ArrayList<>(), partitionsList);
+
+        int[][] result = new int[partitionsList.size()][];
+        for (int i = 0; i < partitionsList.size(); i++) {
+            result[i] = partitionsList.get(i);
+        }
+
+        return result;
+    }
+
+    private void generatePartitions(int remaining, int maxValue, List<Integer> current, List<int[]> result) {
+        if (remaining == 0) {
+            int[] partition = new int[current.size()];
+            for (int i = 0; i < current.size(); i++) {
+                partition[i] = current.get(i);
+            }
+            result.add(partition);
+            return;
+        }
+
+        for (int i = Math.min(maxValue, remaining); i >= 1; i--) {
+            current.add(i);
+            generatePartitions(remaining - i, i, current, result);
+            current.remove(current.size() - 1);
+        }
     }
 
 
-    public static void main()
+    public static void main(String[] args)
     {
+        Scanner in = new Scanner(System.in);
+        MainExercises me = new MainExercises();
 
+        System.out.print("Enter a number: ");
+        int n = in.nextInt();
+
+
+        char[][] triangle = me.generateTriangle(n);
+        for (char[] row : triangle) {
+            for (char c : row) {
+                System.out.print(c);
+            }
+            System.out.println();
+        }
+
+        int[][] matrix = {
+                {1, 2, 3},
+                {4, 5, 6},
+                {7, 8, 9}
+        };
+        int[] spiral = me.spiralTraversal(matrix);
+        for (int num : spiral) {
+            System.out.print(num + " ");
+        }
+        System.out.println();
+
+        int[][] partitions = me.intPartitions(n);
+        for (int[] p : partitions) {
+            for (int i = 0; i < p.length; i++) {
+                System.out.print(p[i]);
+                if (i < p.length - 1) System.out.print(", ");
+            }
+            System.out.println();
+        }
+
+        in.close();
     }
 }