Medium
Quiz
#128 Longest Consecutive Sequence
APPROACH
Given 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: 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
Example 3:
Input: nums = [1,0,1,2]
Output: 3
1 of 4
What is the optimal approach for this problem?