Every email consists of a local name and a domain name, separated by the @ sign.<\/p>\n
For example, in\u00a0 Besides lowercase letters, these emails may contain\u00a0 If you add periods ( If you add a plus ( It is possible to use both of these rules at the same time.<\/p>\n Given a list of\u00a0 Example 1:<\/strong><\/p>\n <\/p>\n Note:<\/strong><\/p>\n <\/p>\n Time complexity: O(n*l) Every email consists of a local name and a domain name, separated by the @ sign. For example, in\u00a0alice@leetcode.com,\u00a0alice\u00a0is the local name, and\u00a0leetcode.com\u00a0is the domain…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[70,47],"tags":[222,426,418,4],"class_list":["post-4221","post","type-post","status-publish","format-standard","hentry","category-hashtable","category-string","tag-easy","tag-email","tag-hashatable","tag-string","entry","simple"],"_links":{"self":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/4221","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/comments?post=4221"}],"version-history":[{"count":4,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/4221\/revisions"}],"predecessor-version":[{"id":4225,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/posts\/4221\/revisions\/4225"}],"wp:attachment":[{"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/media?parent=4221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/categories?post=4221"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zxi.mytechroad.com\/blog\/wp-json\/wp\/v2\/tags?post=4221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}alice@leetcode.com<\/code>,\u00a0alice<\/code>\u00a0is the local name, and\u00a0leetcode.com<\/code>\u00a0is the domain name.<\/p>\n'.'<\/code>s or\u00a0'+'<\/code>s.<\/p>\n'.'<\/code>) between some characters in the\u00a0local name<\/strong>\u00a0part of an email address, mail sent there will be forwarded to the same address without dots in the local name.\u00a0 For example,\u00a0\"alice.z@leetcode.com\"<\/code>\u00a0and\u00a0\"alicez@leetcode.com\"<\/code>\u00a0forward to the same email address.\u00a0 (Note that this rule does not apply for domain names.)<\/p>\n'+'<\/code>) in the\u00a0local name<\/strong>, everything after the first plus sign will be\u00a0ignored<\/strong>. This allows certain emails to be filtered, for example\u00a0m.y+name@email.com<\/code>\u00a0will be forwarded to\u00a0my@email.com<\/code>.\u00a0 (Again, this rule does not apply for domain names.)<\/p>\nemails<\/code>, we send one email to each address in the list.\u00a0\u00a0How many different addresses actually receive mails?<\/p>\nInput: <\/strong>[\"test.email+alex@leetcode.com\",\"test.e.mail+bob.cathy@leetcode.com\",\"testemail+david@lee.tcode.com\"]<\/span>\r\nOutput: <\/strong>2<\/span>\r\nExplanation:<\/strong>\u00a0\"testemail@leetcode.com\" and \"testemail@lee.tcode.com\" <\/span>actually receive mails\r\n<\/pre>\n\n
1 <= emails[i].length\u00a0<= 100<\/code><\/li>\n1 <= emails.length <= 100<\/code><\/li>\nemails[i]<\/code>\u00a0contains exactly one\u00a0'@'<\/code>\u00a0character.<\/li>\n<\/ul>\nSolution:\u00a0<\/strong><\/h1>\n
\nSpace complexity: O(n*l)<\/p>\nC++<\/h2>\n
\/\/ Author: Huahua, 24 ms\r\nclass Solution {\r\npublic:\r\n int numUniqueEmails(vector<string>& emails) {\r\n unordered_set<string> s;\r\n for (const string& email : emails) {\r\n string e;\r\n bool at = false;\r\n bool plus = false;\r\n for (char c : email) {\r\n if (c == '.') {\r\n if (!at) continue;\r\n } else if (c == '@') {\r\n at = true; \r\n } else if (c == '+') {\r\n if (!at) {\r\n plus = true;\r\n continue;\r\n }\r\n } \r\n if (!at && plus) continue;\r\n e += c; \r\n } \r\n s.insert(std::move(e));\r\n }\r\n return s.size();\r\n }\r\n};<\/pre>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"