Longest Consecutive Sequence

128. Longest Consecutive Sequence

Solution

1. Find the smallest number in each sequence
2. Get the length of the sequence by counting the number of larger numbers in the sequence
   Complexity: O(n)

   def longestConsecutive(self, nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    set_nums = set(nums)
    res = 0
       
    for num in nums:
        if num - 1 in set_nums:
            continue
           
        length = 1
        end = num
        while end + 1 in set_nums:
            length += 1
            end += 1
        res = max(length, res)
    return res