1.given a int, print a String[] like : (int = 3, output : "***, * *, ***") 2. given a integer A (eg.555), and another int k (eg.1), find unique number in A of length k that is divisible by A. 3. Given a 2d int matrix, sort the integers by their occurrences in ascending order, if two integers have same occurrence, sort by their values in ascending order. Then put the sorted array to a 2d matrix from button-right index diagonally.