src.longest_cons_seq

Classes

Solution()

class src.longest_cons_seq.Solution

longestConsecutive(nums: list[int]) → int

Thought process

• Use set() for O(1) lookups of neighbors

• Logic is: if n has no Left neighbor => start of sequence otherwise keep incrementing

• If start of sequence found then keep incrementing till no Right neighbor found

• Keep track of longest sequence found

• Basic idea is just to find max length of sequence by recognizing start (n - 1 not in set) and end (n + length (+1) not in set)

Notes

• time complexity : \(O(n)\)

• space complexity : \(O(n)\)