791. 高精度加法

#include <iostream>
#include <vector>
using namespace std;

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

int main()
{
    string a, b;
    cin >> a >> b;
    
    vector<int> 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‘);
    
    auto C = add(A, B);
    
    for (int i = C.size() - 1; i >= 0; -- i)    cout << C[i];
    
    return 0;
}