Longest Consecutive Sequence Length | Dataford Interview Questions

At Stripe, event IDs may arrive out of order. Given an unsorted array of integers nums, return the length of the longest sequence of consecutive integers.

A consecutive sequence contains values that differ by 1, and the elements do not need to appear next to each other in the input array.

Formal Specification

Input: nums, a list of integers
Output: An integer representing the maximum length of any consecutive sequence in nums

Notes

The input may contain duplicates.
An empty array should return 0.

Constraints

0 <= len(nums) <= 10^5
-10^9 <= nums[i] <= 10^9
Input may contain duplicate integers
Aim for O(n) average time complexity

Function Signature

def longest_consecutive(nums):

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