Longest Consecutive SequenceGiven an unsorted array of integers nums, return the length of the longest consecutive elements sequence.You must write an algorithm that runs in O(n) time. Example 1:Input: nums = [100,4,200,1,3,2]Output: 4Explanation: 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: 9Example 3:I..