aloalgoLongest Consecutive Sequence
Hard
You are given an unsorted array of integers nums, find and return the length of the longest sequence of consecutive numbers.
Example 1
Input
[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
[0, 3, 7, 2, 5, 8, 4, 6, 0, 1]
Output
9
Explanation:
The longest consecutive elements sequence is [0, 1, 2, 3, 4, 5, 6, 7, 8]. Therefore its length is 9.
Example 3
Input
[]
Output
0
Explanation:
An empty array has no sequences, so the length is 0.
Input
[100, 4, 200, 1, 3, 2]
Output
4