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();
    }
};