2023-11-24 16:36:38 +0300 MSK

class Solution {
public:
    string gcdOfStrings(string str1, string str2) {
        if (str1 + str2 != str2 + str1) {
            return "";
        }
        unsigned long gcdLength {std::gcd(str1.size(), str2.size())};
        return str1.substr(0, gcdLength);
    }
};