66 Plus One

public class Solution {
    public int[] plusOne(int[] digits) {
        int carry = 1;
        for (int i = digits.length -1; i >= 0; i--) {
            int sum = digits[i] + carry;
            carry = sum / 10;
            digits[i] = sum % 10;
        }
        if (carry == 0) {
            return digits;
        }
        
        int[] res = new int[digits.length + 1];
        res[0] = carry;
        for (int i = 1; i<digits.length + 1; i++) {
            res[i] = digits[i - 1];
        }
        return res;
    }
}