【leetcode 】最长连续序列

class Solution:
    def longestConsecutive(self, nums: List[int]) -> int:
        cur_len = 0
        nums = set(nums)
        ans = 0
        for item in nums:
            if item-1 not in nums:
                cur_num = item
                cur_len = 1
                while cur_num+1 in nums:
                    cur_len +=1
                    cur_num +=1
                ans = max(cur_len, ans)
        return ans