class Solution:
    def longestConsecutive(self, nums):

        longest_streak = 0
        num_set = set(nums)

        for i in range(len(nums)):
            # check if the current element is the first elements
            # this comes from a DP approach and  done to avoid repeat iterations
            if (nums[i] - 1) not in num_set:

                current_streak = 1
                while((nums[i] + current_streak) in num_set):
                    current_streak += 1

                longest_streak = max(current_streak, longest_streak)

        return longest_streak