input: Write a python function to find the longest consecutive sequence in an array.
  assert longest_consecutive_sequence([3, 5, 2, 7, 6, 4, 8, 9, 10, 11]) == [6, 7, 8, 9, 10, 11]
  assert longest_consecutive_sequence([1, 2, 3, 5, 6, 7, 8]) == [5, 6, 7, 8]
  assert longest_consecutive_sequence([10, 12, 11, 14, 13, 15, 16, 17]) == [10, 11, 12, 13, 14, 15, 16, 17]
output: def longest_consecutive_sequence(nums):
      nums = set(nums)
      longest_seq = []
      
      for num in nums:
          if num - 1 not in nums:  # start of a sequence
              current_num = num
              current_seq = []
              
              while current_num in nums:
                  current_seq.append(current_num)
                  current_num += 1
              
              if len(current_seq) > len(longest_seq):
                  longest_seq = current_seq
                  
      return longest_seq