因为想要加减乘除形式统一，所以除法结束之后还要reverse一下， 倒置数列

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;


vector<int> div(vector<int> &A, int b, int &r)
{
    vector<int> C;
    int t = 0;
    for(int i = A.size() - 1; i >= 0; i -- )
    {
        t = t * 10 + A[i];
        C.push_back(t / b);
        t = t % b;
    }
    r = t;
    reverse(C.begin(), C.end());
    while(C.size() > 1 && C.back() == 0) C.pop_back();
    return C;
}
int main()
{
    string a;
    int b, r;
    cin >> a >> b;
    vector<int> A;
    for(int i = a.size() - 1; i >= 0; i -- ) A.push_back(a[i] - '0');
    auto C = div(A, b, r);
    for(int i = C.size() - 1; i >= 0; i -- ) printf("%d", C[i]);
    cout<< endl << r << endl;
    return 0;
}