Problem Statement

Given an unsorted array of integers, find the length of the longest consecutive sequence of numbers in it. A consecutive sequence means the numbers in the sequence are contiguous without any gaps. For instance, 1, 2, 3, 4 is a consecutive sequence, but 1, 3, 4, 5 is not.

Examples

1. • Input: [10, 11, 14, 12, 13]
   • Output: 5
   • Justification: The entire array forms a consecutive sequence from 10 to 14.
2. • Input: [3, 6, 4, 100, 101, 102]
   • Output: 3
   • Justification: There are two consecutive sequences, [3, 4] and [100,101,102]. The latter has a maximum length of 3.
3. • Input: [4, 3, 6, 2, 5, 8, 4, 7, 0, 1]
   • Output: 9
   • Justification: The longest consecutive sequences here are [0, 1, 2,, 3, 4, 5, 6, 7, 8].
4. • Input: [7, 8, 10, 11, 15]
   • Output: 2
   • Justification: The longest consecutive sequences here are [7,8] and [10,11], both of length 2.

Constraints:

• 0 <= nums.length <= 10⁵
• -10⁹ <= nums[i] <= 10⁹

Try it yourself

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