Doing main exercises

src/.idea/.gitignore

@@ -0,0 +1,10 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Ignored default folder with query files
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
+# Editor-based HTTP Client requests
+/httpRequests/

src/.idea/misc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" project-jdk-name="25" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

src/.idea/modules.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/main/main.iml" filepath="$PROJECT_DIR$/main/main.iml" />
+      <module fileurl="file://$PROJECT_DIR$/.idea/src.iml" filepath="$PROJECT_DIR$/.idea/src.iml" />
+      <module fileurl="file://$PROJECT_DIR$/test/test.iml" filepath="$PROJECT_DIR$/test/test.iml" />
+    </modules>
+  </component>
+</project>

src/.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$/.." vcs="Git" />
+  </component>
+</project>

src/main/java/MainExercises.java

@@ -1,3 +1,6 @@
+import java.util.ArrayList;
+import java.util.List;
+
 public class MainExercises
 {
     /*
@@ -18,11 +21,21 @@ 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;
-
+    public char[][] generateTriangle(int n)
+    {
+        char[][] triangle = new char[n][];
+        for(int i = 0; i < n; i++)
+        {
+            triangle[i] = new char[i+1];
+            for(int j = 0; j <= i; j++)
+            {
+                if(i == 0 || j == 0 || i == j || i == n-1)
+                    triangle[i][j] = '*';
+                else
+                    triangle[i][j] = ' ';
+            }
+        }
+        return triangle;
     }
 
 
@@ -57,9 +70,38 @@ public class MainExercises
            - Number of rows:    matrix.length
            - Number of columns: matrix[0].length (if rectangular)
    */
-    public int[] spiralTraversal(int[][] matrix) {
-        // todo
-        return null;
+    public int[] spiralTraversal(int[][] matrix)
+    {
+
+        int m = matrix.length;
+        int n = matrix[0].length;
+        int x = 0;
+        int y = 0;
+        int idx = 0;
+
+        int[] numbers = new int[m * n];
+        boolean[][] visitedCell = new boolean[m][n];
+        int[][] dir = {{0,1},{1,0},{0,-1},{-1,0}};
+
+        for(int i = 0; i < (m * n); i++)
+        {
+            numbers[i] = matrix[x][y];
+            visitedCell[x][y] = true;
+
+            int nextX = x + dir[idx][0];
+            int nextY = y + dir[idx][1];
+
+            if (nextX < 0 || nextX >= m || nextY < 0 || nextY >= n || visitedCell[nextX][nextY] == true)
+            {
+                idx = (idx + 1) % 4;
+
+                nextX = x + dir[idx][0];
+                nextY = y + dir[idx][1];
+            }
+            x = nextX;
+            y = nextY;
+        }
+        return numbers;
     }
 
     /*
@@ -90,11 +132,38 @@ public class MainExercises
         body to use them instead of arrays.
     */
 
-    public int[][] intPartitions(int n) {
-        // todo
-        return null;
+    public int[][] intPartitions(int n)
+    {
+        List<int[]> result = new ArrayList<>();
+        findPartitions(n, n, new ArrayList<>(), result);
+        return result.toArray(new int[result.size()][]);
     }
 
+    private void findPartitions(int r, int max, List<Integer> list, List<int[]> finalList)
+    {
+        if (r == 0)
+        {
+            int[] partition = new int[list.size()];
+            for (int i = 0; i < list.size(); i++)
+            {
+                partition[i] = list.get(i);
+            }
+            finalList.add(partition);
+            return;
+        }
+
+        if (r >= max)
+        {
+            list.add(max);
+            findPartitions(r - max, max, list, finalList);
+            list.remove(list.size() - 1);
+        }
+
+        if (max > 1)
+        {
+            findPartitions(r, max - 1, list, finalList);
+        }
+    }
 
     public static void main()
     {