题目：

题解：

class Solution:def longestConsecutive(self, nums: List[int]) -> int:longest_streak = 0num_set = set(nums)for num in num_set:if num - 1 not in num_set:current_num = numcurrent_streak = 1while current_num + 1 in num_set:current_num += 1current_streak += 1longest_streak = max(longest_streak, current_streak)return longest_streak