929. Unique Email Addresses

最新推荐文章于 2024-08-04 09:50:56 发布

BigFatSheep

最新推荐文章于 2024-08-04 09:50:56 发布

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分类专栏： Leetcode Easy

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本文探讨了如何解析和标准化电子邮件地址，通过去除点号和加号后的字符，实现对邮件地址的有效去重，以确定实际接收邮件的不同地址数量。

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Description

Every email consists of a local name and a domain name, separated by the @ sign.

For example, in alice@leetcode.com, alice is the local name, and leetcode.com is the domain name.

Besides lowercase letters, these emails may contain '.'s or '+'s.

If you add periods (’.’) between some characters in the local name part of an email address, mail sent there will be forwarded to the same address without dots in the local name. For example, "alice.z@leetcode.com" and "alicez@leetcode.com" forward to the same email address. (Note that this rule does not apply for domain names.)

If you add a plus (’+’) in the local name, everything after the first plus sign will be ignored. This allows certain emails to be filtered, for example m.y+name@email.com will be forwarded to my@email.com. (Again, this rule does not apply for domain names.)

It is possible to use both of these rules at the same time.

Given a list of emails, we send one email to each address in the list. How many different addresses actually receive mails?

Example 1:

Input: [“test.email+alex@leetcode.com”,“test.e.mail+bob.cathy@leetcode.com”,“testemail+david@lee.tcode.com”]
Output: 2
Explanation: "testemail@leetcode.com" and "testemail@lee.tcode.com" actually receive mails

Note:

1 <= emails[i].length <= 100
1 <= emails.length <= 100
Each emails[i] contains exactly one ‘@’ character.

Problem URL

Solution

给一串String代表邮箱地址，去掉里面的“.” 和+，找到所有的不同邮箱地址的数量。

Split the email address by “@” then substring + and replace . with “”. Add them together to a hash set.

Code

class Solution {
    public int numUniqueEmails(String[] emails) {
        Set<String> set = new HashSet<>();
        for (String email : emails){
            String[] names = email.split("@");
            String domain = names[1];
            int plusIndex = names[0].indexOf("+");
            String local = names[0].substring(0, plusIndex);
            local = local.replace(".", "");
            set.add(local + "@" + domain);
        }
        return set.size();
    }
}