摘要：
加法： 减法： 乘法： 1 std::string StringMul(const std::string& left, const std::string& right) { 2 bool flag1 = (left[0] == '-'), flag2 = (right[0] == '-'); 3 阅读全文
摘要：
A. Palindromic Supersequence You are given a string A. Find a string B, where B is a palindrome and A is a subsequence of B. A subsequence of a string 阅读全文