import java.util.*;

/* Google oa

Here are a bunch of emails. You find some of them may be duplicate. Let's say an email address contains a local name

and a domain name. "ab@email.com" "ab" is the local name and "gmail.com" is the domain name.

local name: igore all dots '.' between characters & remove all characters after "+"

ex: "dup....licate+a@gmail.com" equals to "duplicate@email.com"

* */

public class groupEmail {

public static void main(String[] args){

groupEmail obj = new groupEmail();

String[] emails = {"ab@gmail.com", "a.....b@gmail.com", "a+b@abc.com", "..a...@abc.com"};

System.out.println(obj.group(emails));

}

// return the number of groups which contains more that 2 email addresses

private int group(String[] emails){

Map<String, Integer> map = new HashMap<>();

int counter = 0;

for(String email : emails){

// helper(email)

String pattern = extract(email);

//map.putIfAbsent(pattern, 0);

map.put(pattern, map.getOrDefault(pattern,0)+1);

if(map.get(pattern) == 2){

counter ++;

}

}

return counter;

}

private String extract(String email){

StringBuilder sb = new StringBuilder();

int index = email.indexOf('@');

String name = email.substring(0,index);

String domain = email.substring(index, email.length());

for(int i = 0; i < name.length(); i++){

if(name.charAt(i) == '.'){

continue;

}

else if(name.charAt(i) == '+'){

break;

}else{

sb.append(name.charAt(i));

}

}

System.out.println(sb.toString()+domain);

return sb.toString()+domain;

}

}