better soln

0128_longest-consecutive-sequence/python3/solution.py

@@ -0,0 +1,32 @@
+# Time: O(N)
+# Space: O(N)
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        visited = {}
+        
+        for _, num in enumerate(nums):
+            visited[num] = False
+            
+        maxl = 0
+        
+        for _, num in enumerate(nums):
+            if visited[num]:
+                continue
+            
+            l = 1
+            prev = num - 1
+            while prev in visited:
+                visited[prev] = True
+                l += 1
+                prev -= 1
+            
+            next = num + 1
+            while next in visited:
+                visited[next] = True
+                l += 1
+                next += 1
+            
+            maxl = max(maxl, l)
+        
+        return maxl
+