[Leo] 5th Week solutions (added rest TC/SC for longest-consecutive q)

Author: leokim0922

longest-consecutive-sequence/Leo.py

@@ -14,3 +14,5 @@ def longestConsecutive(self, nums: List[int]) -> int:
                 longest = max(length, longest)
 
         return longest
+
+        ## TC: O(n), SC: O(n)