solved longest-consecutive-sequence.

Author: sangbeenmoon

longest-consecutive-sequence/sangbeenmoon.py

@@ -0,0 +1,18 @@
+# 30분 내로 풀지 못함. 풀이를 참고하였음.
+# idea : x - 1 이 존재하지 않는 x 값에서만 loop 를 실행한다.
+# time O(n) : 모든 숫자를 많아야 1,2번 방문.
+# space O(n)
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        s = set(nums)
+        answer = 0
+        for num in s:
+            if num - 1 not in s:
+                cur = num - 1
+                length = 0
+                while cur + 1 in s:
+                    cur = cur + 1
+                    length = length + 1
+                answer = max(answer , length)
+
+        return answer