128. Longest Consecutive Sequence
![https://leetcode.com/problems/longest-consecutive-sequence/] Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence. 1 2 3 4 5 6 7 8 9 10 Example 1: Input: nums = [100,4,200,1,3,2] Output: 4 Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4. Example 2: Input: nums = [0,3,7,2,5,8,4,6,0,1] Output: 9 Constraints: ...