Longest Consecutive Sequence Problem Statement

You are provided with an unsorted array/list ARR of N integers. Your task is to determine the length of the longest consecutive sequence present in the array.

Explanation:

The consecutive sequence should be in the form [NUM, NUM + 1, NUM + 2, ..., NUM + L] where NUM is the starting integer of the sequence and L + 1 is the length of the sequence.

Note:

If the array contains any duplicates, consider only one occurrence of the number in the consecutive sequence.

Input:

The first line of input contains a single integer 'T', representing the number of test cases or queries.

The first line of each test case contains integer 'N' denoting the size of the array.

The second line of each test case contains 'N' space-separated integers, the elements of the array.

Output:

For each test case, output a single integer on a new line representing the length of the longest consecutive sequence.

Example:

Input: ARR = [9,5,4,9,10,10,6]
Output: 3
Explanation: The longest consecutive sequence is [4,5,6].

Constraints:

• 1 <= T <= 10
• 1 <= N <= 10^5
• -10^9 <= ARR[i] <= 10^9

Note:

You do not need to print the expected output; it's already handled. Just implement the required function.

Performance consideration:

Can you solve this problem with O(N) time complexity and O(N) space complexity?