参考答案：

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

using namespace std;

vector<int>A, B;

vector<int>add(vector<int>& A, vector<int>& B)
{
    if (A.size() < B.size()) return add(B, A);

    vector<int> C;
    int t = 0;
    for (int i = 0; i < A.size(); ++i)
    {
        t += A[i];
        if (i < B.size()) t += B[i];
        C.push_back(t % 10);
        t /= 10;
    }

    if (t) C.push_back(t);
    reverse(C.begin(), C.end());

    return C;
}
int main()
{
    string a, b;

    cin >> a >> b;

    for (int i = a.size() - 1; i >= 0; --i) A.push_back(a[i] - '0');
    for (int i = b.size() - 1; i >= 0; --i) B.push_back(b[i] - '0');

    vector<int> C = add(A, B);

    for (int i = 0; i < C.size(); ++i) cout << C[i];

    return 0;
}