929. Unique Email Addresses
setを思いつければ簡単。
class Solution { public: int numUniqueEmails(vector<string>& emails) { set<string> num; for(string email: emails){ string checkedEmail; for(int i=0; email[i]!='@'; i++ ){ if(email[i] == '+'){ break; } else if(email[i] == '.'){ continue; } else{ checkedEmail += email[i]; } } int j = email.find('@'); checkedEmail += email.substr(j, email.length()-j); num.insert(checkedEmail); } return num.size(); } };