public class Solution {

    public int[] plusOne(int[] digits) {

        for (int i = digits.length - 1; i >=0; i--) {

            if (digits[i] < 9) {

                digits[i]++;
                return digits;

            }

            digits[i] = 0;

        }

        int[]  result = new int [digits.length + 1];
        result[0] = 1;

        return result;

    }

}

Create : 66 Plus One