This  for question number 260. What is the time complexity and space complexity? The array \'ans\' will have only 2 elements. so space should be O(1) and time will be O(n) (n times O(1) lookup in set). Am i right?\n\n```\nclass Solution(object):\n    def singleNumber(self, nums):\n        """\n        :type nums: List[int]\n        :rtype: List[int]\n        """\n        if not nums:\n            return [0,0]\n        ans=set()\n        for i in nums:\n            if i in ans:\n                ans.remove(i)\n            else:\n                ans.add(i)\n        return ans\n```

This  for question number 260. What is the time complexity and space complexity? The array \'ans\' will have only 2 elements. so space should be O(1) and time w