LeetCode 066 Plus one

タイトル:
https://leetcode.com/problems/plus-one/
Given a non-negative number represented as an array of digits, plus one to the number.
The digits are stored such that the most significant digit is at the head of the list. タイトルは簡単ですが、最上位が9の場合、結果を格納するために長い1つの新しい配列をnewする必要があることに注意してください.

public class Solution {
    public int[] plusOne(int[] digits) {
        if (digits == null || digits.length == 0) return digits;
        int carry = 1;
        for (int i=digits.length - 1; i >= 0; i--) {
            digits[i] = digits[i] + carry;
            if (digits[i] < 10) {
                return digits;
            } else {
                digits[i] = 0;
                carry = 1;
            }
        }
        int[] newDigits = new int[digits.length + 1];
        newDigits[0] = 1;
        System.arraycopy(digits, 0, newDigits, 1, digits.length);
        return newDigits;
    }
}