class Solution {public:    vector<int> plusOne(vector<int> &digits) {        int i,k=0;        int a[100];        for(i=digits.size()-1;i>=0;i--)           a[k++]=digits[i];        int c=1;        for(i=0;i<k;i++)        {            int sum=a[i]+c;            a[i]=sum%10;            c=sum/10;        }        if(c!=0) a[k++]=c;        vector<int> vec;        for(i=k-1;i>=0;i--) vec.push_back(a[i]);        return vec;    }};