class Solution { public: string decodeWangzai(string password, int n) { for(int i=0; i<password.size(); i++) { int offset = n % 26; // 处理n大于26的情况 if(password[i] - offset < 'a') { password[i] = 'z' - (offset - (password[i] - 'a') - 1); } else { password[i] = password[i] - offset; } } return password; } };