leetcode-com-explore-challenge-card-july-leetcoding-challenge-544-week-1-july-1st-july-7th-3382.cpp

class Solution {
public:
    vector<int> plusOne(vector<int>& digits) {
        int n=digits.size();
        for(int i=n-1;i>=0;i--){
            if(digits[i]==9){
                digits[i]=0;
            }
            else {
                digits[i]+=1;
                return digits;
            }   
        }
        if(digits[0]==0){
            digits[0]=1;
            digits.push_back(0);
        }
        return digits;   
    }
};