Unique Email Addresses

给一组字符串, 表示emails. 其中.可以忽略, +忽略其后边的字符串. 求有多少不一样的emails.

class Solution {
    public int numUniqueEmails(String[] emails) {
        Set<String> set = new HashSet<>();
        for(String s : emails) {
            String s1 = s.split("@")[0];
            String s2 = s.split("@")[1];
            s1 = s1.replaceAll("\\.","");
            if(s1.indexOf('+') != -1)
                s1 = s1.substring(0, s1.indexOf('+'));
            set.add(s1+"@"+s2);
        }
        return set.size();
    }
}