Тормозной механизм

#include<iostream>
#include<fstream>
#include<string>
#include<algorithm>
#define all(container) container.begin(), container.end()
#define fors(counter, start, finish) for (int counter = start; counter < finish; ++counter)
#define forb(counter, start, finish) for (int counter = start; counter >= finish; --counter)
#define vec(type) std::vector<type>
#define dvec(type) std::vector<std::vector<type>>

int main() {

    std::ifstream fin("input.txt");

    std::string s, s2;
    fin >> s >> s2;
    if (s.size() < s2.size()) {
        swap(s, s2);
    }
    std::string s1 = "";
    fors(i, 0, s2.size())
        s1.push_back('0');
    fors(i, 0, s.size())
        s1.push_back(s[i]);
    fors(i, 0, s2.size())
        s1.push_back('0');

    int ans = 1000000;
    fors(i, 0, s1.size() - s2.size() + 1) {
        int j = i;
        while (s1[j] - '0' + s2[j - i] - '0' <= 3 && j - i < s2.size())
            ++j;
        if (j - i == s2.size()) {
            if (i < s2.size()) {
                ans = ans < s.size() + s2.size() - i ? ans : s.size() + s2.size() - i;
            }
            else if (i > s.size()) {
                ans = ans < i ? ans : i;
            }
            else {
                ans = ans < s.size() ? ans : s.size();
            }
        }
    }

    std::cout << ans << std::endl;

    return 0;
}