题：https://leetcode.com/contest/weekly-contest-108/problems/unique-email-addresses/
题目
Every email consists of a local name and a domain name, separated by the @ sign.
For example, in [email protected], 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, "[email protected]" and "[email protected]" 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 [email protected] will be forwarded to [email protected]. (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: ["[email protected]","[email protected]","[email protected]"]
Output: 2
Explanation: "[email protected]" and "[email protected]" actually receive mails
Note:
1 <= emails[i].length <= 100
1 <= emails.length <= 100
Each emails[i] contains exactly one ‘@’ character.
题目大意
对字符串进行如下规则处理。
对于@前子串，删除’.‘字符，删除’+'以后的字符。
返回 处理后不同字符串的数量
思路
StringBuilder 对字符串进行处理
set 进行去重
class Solution {
public int numUniqueEmails(String[] emails) {
Set<String> strSet = new HashSet<>();
for(int i = 0 ;i <emails.length;i++){
StringBuilder strbuilder = new StringBuilder(emails[i]);
int end = strbuilder.indexOf("@");
int j = 0;
while (j < end){
if(strbuilder.charAt(j) == '.'){
strbuilder.deleteCharAt(j);
end--;
}
else if(strbuilder.charAt(j) == '+'){
strbuilder.delete(j,end);
break;
}
else
j++;
}
strSet.add(strbuilder.toString());
}
return strSet.size();
}
}