This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
The problem with dividing is that you have to loop twice; once to get to know the array size, then another to fill it. Even if you use a List you still need to loop twice; the second loop to convert a List<Integer> to an int.
Then again, converting to String and then converting each separate character to a digit (using Character.digit) also is two loops; the int to String also has a loop.
I don't think you can get past a double loop. That leaves an option between ease (int -> String, char -> int) and efficiency (dividing). Well, if dividing is more efficient; I'd have to test first.