128. Longest Consecutive Sequence

• turn into set, find element with no previous element in the set, and continue from there
• ensure the number is a start of a sequence

class Solution(object):
    def longestConsecutive(self, nums):
        numbers = set(nums)

        maximum = 0

        for num in nums:
            if (num - 1) in numbers:
                continue
            else:
                i = num
                while i + 1 in numbers:
                    i = i + 1
                maximum = max(maximum, i - num + 1)

        return maximum