Longest Consecutive Sequence Problem Statement

You are given an unsorted array/list ‘ARR’ of ‘N’ integers. Your task is to return the length of the longest consecutive sequence.

The consecutive sequence is of 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 there are any duplicates in the given array, we will count only one of them in the consecutive sequence.

Input:

The first line of input contains a single integer ‘T’, representing the number of test cases. Then the ‘T’ test cases follow. The first line of each test case contains an integer ‘N’, denoting the size of the array. The second line of each test case contains ‘N’ space-separated integers, elements of the array.

Output:

For each test case, print an integer in a single line that represents 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 <= 10⁵
• -10⁹ <= ARR[i] <= 10⁹

Time Limit: 1 sec