class Solution {
public:
    vector<int> plusOne(vector<int> &digits) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int carry = 1;
        for (int i = digits.size() - 1; i >= 0; --i)
        {
            int sum = digits[i] + carry;
            digits[i] = sum % 10;
            carry = sum / 10;
            if (carry == 0)
            {
                break;
            }
        }
        if (carry == 1)
        {
            digits.insert(digits.begin(), 1);
        }
        return digits;
    }
};