128. Longest Consecutive Sequence

Leetcode

Neetcode

Code

class Solution(object):
    def longestConsecutive(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        hash_set = set(nums)
        res = 0
 
        for n in nums:
            if (n-1) not in hash_set:
                length = 0
                while (n+length) in hash_set:
                    length += 1
                res = max(length, res)
 
        return res