(https://leetcode-cn.com/problems/greatest-common-divisor-of-strings/solution/zi-fu-chuan-de-zui-da-gong-yin-zi-by-leetcode-solu/有详细的说明) AC代码: classSolution {public:stringgcdOfStrings(stringstr1,stringstr2) {if(str1 + str2 != str2 + str1)return"";returnstr1.substr(0, __...