python - How do I improve remove duplicate algorithm? -

my interview question need return length of array removed duplicates can leave @ 2 duplicates.

for example, [1, 1, 1, 2, 2, 3] new array [1, 1, 2, 2, 3]. new length 5. came algorithm o(2n) believe. how can improve fastest.

def removeduplicates(nums):     if nums none:         return 0      if len(nums) == 0:         return 0      if len(nums) == 1:         return 1      new_array = {}     num in nums:         new_array[num] = new_array.get(num, 0) + 1      new_length = 0     key in new_array:         if new_array[key] > 2:             new_length = new_length + 2         else:             new_length = new_length + new_array[key]      return new_length  new_length = removeduplicates([1, 1, 1, 2, 2, 3]) assert new_length == 5 

my first question algorithm correct?

your logic correct simpler method reach goal had mentioned in question.

here logic.

myl = [1, 1, 1, 2, 2, 3, 1, 1, 1, 2, 2, 3, 1, 1, 1, 2, 2, 3]  newl = []  in myl:     if newl.count(i) != 2:         newl.append(i)  print newl [1, 1, 2, 2, 3, 3] 

hope helps.