Python solution
O(n) time, O(n) space, where n is the total length of all emails.\n\n\nclass Solution(object):\n    def numUniqueEmails(self, emails):\n        """\n        :ty
`O(n)` time, `O(n)` space, where `n` is the total length of all emails.\n\n```\nclass Solution(object):\n    def numUniqueEmails(self, emails):\n        """\n        :type emails: List[str]\n        :rtype: int\n        """\n        seen = set()\n        for email in emails:\n            local, domain = email.split(\'@\')\n            local = local.split(\'+\')[0]\n            local = local.replace(\'.\',\'\')\n            seen.add(local+\'@\'+domain)\n        return len(seen)\n```
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