> For the complete documentation index, see [llms.txt](https://dfine.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dfine.gitbook.io/leetcode/929.unique_email_address.md).

# 929.Unique Email Address

**929.Unique Email Addresses**

难度:Easy

> 每封电子邮件都由一个本地名称和一个域名组成，以 @ 符号分隔。 例如，在 <alice@leetcode.com>中， alice 是本地名称，而 leetcode.com 是域名。 除了小写字母，这些电子邮件还可能包含 '.' 或 '+'。 如果在电子邮件地址的本地名称部分中的某些字符之间添加句点（'.'），则发往那里的邮件将会转发到本地名称中没有点的同一地址。例如，"<alice.z@leetcode.com>” 和 “<alicez@leetcode.com>” 会转发到同一电子邮件地址。 （请注意，此规则不适用于域名。） 如果在本地名称中添加加号（'+'），则会忽略第一个加号后面的所有内容。这允许过滤某些电子邮件，例如 <m.y+name@email.com> 将转发到 <my@email.com>。 （同样，此规则不适用于域名。） 可以同时使用这两个规则。 给定电子邮件列表 emails，我们会向列表中的每个地址发送一封电子邮件。实际收到邮件的不同地址有多少？

```
示例：

输入：["test.email+alex@leetcode.com","test.e.mail+bob.cathy@leetcode.com","testemail+david@lee.tcode.com"]
输出：2
解释：实际收到邮件的是 "testemail@leetcode.com" 和 "testemail@lee.tcode.com"。
 

提示：

1 <= emails[i].length <= 100
1 <= emails.length <= 100
每封 emails[i] 都包含有且仅有一个 '@' 字符。
```

代码如下：

```
class Solution {
public:
    int numUniqueEmails(vector<string>& emails) {
        unordered_set<string> uni_email;
        for(auto email: emails)
        {
            int flag=1;
            string tmp;
            for(auto c: email)
            {
                
                if(c=='.' && flag==1) continue;
                if(c=='@') flag=2;
                if(c=='+' && flag==1) flag=0;
                if(flag) tmp+=c;
            }
            uni_email.insert(tmp);
        }
        return uni_email.size();
    }
};
```


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