matin mortazavi / exercises + bonus

src/main/java/MainExercises.java

@@ -1,5 +1,7 @@
-public class MainExercises
-{
+import java.util.ArrayList ;
+import java.util.List;
+
+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 " "
@@ -20,13 +22,23 @@ public class MainExercises
  */
     public char[][] generateTriangle(int n) {
 
-        // todo
-        return null;
+        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;
 
     }
 
 
-
     /*
        SPIRAL TRAVERSAL OF A RECTANGULAR MATRIX
 
@@ -57,11 +69,52 @@ 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 rows = matrix.length;
+        int col = matrix[0].length;
+
+        int size = 0 ;
+        boolean increase = true;
+        int range = rows * col ;
+        int check = 0 ;
+        int UP = 0 ;
+        int DOWN = rows-1 ;
+        int LEFT = 0 ;
+        int RIGHT = col -1;
+
+       int[] newmat = new int[rows*col] ;
+       while (UP <= DOWN && LEFT<= RIGHT) {
+           for (int j = LEFT; j <= RIGHT; j++) {
+               newmat[size] = matrix[UP][j];
+               size++;
+           }
+
+           UP++;
+           for (int i = UP; i <= DOWN; i++) {
+               newmat[size] = matrix[i][RIGHT ];
+               size++;
+           }
+           RIGHT--;
+           if(UP <= DOWN) {
+               for (int j = RIGHT ; j >= LEFT; j--) {
+                   newmat[size] = matrix[DOWN ][j];
+                   size++;
+               }
+               DOWN--;
+           }
+           if(LEFT <= RIGHT) {
+               for (int i = DOWN ; i >= UP; i--) {
+                   newmat[size] = matrix[i][LEFT];
+                   size++;
+               }
+               LEFT++;
+           }
+
+       }
+        return newmat ;
     }
 
+
     /*
         integer partitioning is a combinatorics problem in discreet maths
         the problem is to generate sum numbers which their summation is the input number
@@ -90,9 +143,41 @@ public class MainExercises
         body to use them instead of arrays.
     */
 
+
     public int[][] intPartitions(int n) {
-        // todo
-        return null;
+       ArrayList <int[]> all = new ArrayList<>() ;
+       ArrayList<Integer>list = new ArrayList<>() ;
+       part(n , n ,list , all);
+       return convertTo2DArray(all) ;
+
+
+    }
+    public static int[][] convertTo2DArray(ArrayList<int[]> all) {
+        int [][] mat = new int [all.size()][] ;
+        for (int i = 0 ; i < all.size() ; i ++ )
+        {
+            mat[i] = all.get(i) ;
+        }
+        return mat;
+    }
+    public static void part(int rem , int max , ArrayList<Integer> list , ArrayList<int []> all )
+    {
+        if (rem == 0)
+        {
+            int[] final1 =  new int [list.size()] ;
+            for (int i = 0 ; i < list.size(); i ++ )
+            {
+                final1[i] = list.get(i) ;
+            }
+            all.add(final1) ;
+            return;
+        }
+        for (int i = Math.min(rem , max) ; i >=1 ; i --  )
+        {
+            list.add(i) ;
+            part(rem-i , i , list, all );
+            list.remove(list.size()-1) ;
+        }
     }