Arrays - medium - longest consecutive sequence implementation

Author: rajithst

arrays/medium/longest_consecutive_sequence.py

@@ -0,0 +1,28 @@
+from typing import List
+
+
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+
+        longest_range = 0
+        mem = {}
+        for i in nums:
+            mem[i] = True
+
+        for i in nums:
+            if not mem[i]:
+                continue
+            mem[i] = False
+            current_length = 1
+            next_val = i + 1
+            prev_val = i - 1
+            while prev_val in mem:
+                mem[prev_val] = False
+                current_length += 1
+                prev_val -= 1
+            while next_val in mem:
+                mem[next_val] = False
+                current_length += 1
+                next_val += 1
+            longest_range = max(longest_range, current_length)
+        return longest_range