Solved 128. Longest Consecutive Sequence problem

Author: KwonNayeon

longest-consecutive-sequence/KwonNayeon.py

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+"""
+Title: 128. Longest Consecutive Sequence
+Link: https://leetcode.com/problems/longest-consecutive-sequence/
+
+Question:
+    - Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence.
+    - You must write an algorithm that runs in O(n) time.
+
+Constraints:
+    - 0 <= nums.length <= 10^5
+    - -10^9 <= nums[i] <= 10^9
+
+Time Complexity:
+    - O(n log n)
+Space Complexity:
+    - O(n)
+
+Notes:
+    - sorted(nums)를 사용하면 TC가 O(n log n)이 되어 문제의 조건을 충족하지 못하지만, 이 방법이 제가 생각해서 풀 수 있는 최선이라 일단 이대로 제출합니다! 다른 분들 답안 참고하여 다시 풀어보겠습니다 :)
+"""
+
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        nums = sorted(nums)
+        max_length = 0
+        current_length = 1
+
+        for i in range(1, len(nums)):
+            if nums[i] == nums[i-1] + 1:
+                current_length += 1
+            elif nums[i] == nums[i-1]:
+                continue
+            else:
+                max_length = max(max_length, current_length)
+                current_length = 1
+
+        max_length = max(max_length, current_length)
+        return max_length