JavaScript One-Liner, two solutions (76ms 88ms)
the one with Regexp, 76ms\n\nreturn new Set(emails.map(email => `${/(.*?)\\+/.exec(email.split(\'@\')[0].replace(/\\./g,\'\'))[1]}@${email.split(\'@\')[1]}`)).s
the one with Regexp, 76ms\n```\nreturn new Set(emails.map(email => `${/(.*?)\\+/.exec(email.split(\'@\')[0].replace(/\\./g,\'\'))[1]}@${email.split(\'@\')[1]}`)).size\n```\nanother, 88ms\n```\nreturn new Set(emails.map(email => `${email.split(\'@\')[0].split(\'+\')[0].split(\'.\').join(\'\')}@${email.split(\'@\')[1]}`)).size\n```\n\n
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