Plus-One

class Solution {
public:

    vector<int> plusOne(vector<int>& digits) {
        int i = digits.size()-1;
        int carry = 0;

        while(i >= 0){
            if(digits[i] != 9){
                digits[i]++;
                carry = 0;
                break;
            }
            else {
                digits[i] = 0;
                carry = 1;
                i--;
            }
        }

        if(carry == 1){
            // it means we need to resize the array and insert 1 into the beginning
            digits.insert(digits.begin(), 1);
        }

        return digits;
    }
};