LeetCode-929 Unique Email Addresses Solution (with Java)

1. Description:

Notes:

2. Examples:

3.Solutions:

/**
 * Created by sheepcore on 2019-02-24
 */
class Solution {
        public int numUniqueEmails(String[] emails) {
        Set<String> normalized = new HashSet<>(); // used to save simplified email address, cost O(n) sapce.
        for (String email : emails) {
            String[] parts = email.split("@"); // split into local and domain parts.
            String[] local = parts[0].split("\\+"); // split local by '+'.
            normalized.add(local[0].replace(".", "") + "@" + parts[1]); // remove all '.', and concatenate '@' and domain.        
        }
        return normalized.size();
    }
}