adding algo

src/my_project/interviews/top_150_questions_round_22/ex_45_longest_consecutive_sequence.py

@@ -0,0 +1,28 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        if not nums:
+            return 0
+
+        # Convert to set for O(1) lookup
+        num_set = set(nums)
+        max_length = 0
+
+        for num in num_set:
+            # Only start counting if this is the beginning of a sequence
+            # (i.e., num - 1 is not in the set)
+            if num - 1 not in num_set:
+                current_num = num
+                current_length = 1
+
+                # Count consecutive numbers
+                while current_num + 1 in num_set:
+                    current_num += 1
+                    current_length += 1
+
+                max_length = max(max_length, current_length)
+
+        return max_length
+

tests/test_150_questions_round_22/test_45_longest_consecutive_sequence_round_22.py

@@ -0,0 +1,23 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_22\
+.ex_45_longest_consecutive_sequence import Solution
+
+class LongestConsecutiveSequenceTestCase(unittest.TestCase):
+
+    def test_first_pattern(self):
+        solution = Solution()
+        output = solution.longestConsecutive(nums = [100,4,200,1,3,2])
+        target = 4
+        self.assertEqual(output, target)
+
+    def test_second_pattern(self):
+        solution = Solution()
+        output = solution.longestConsecutive(nums = [0,3,7,2,5,8,4,6,0,1])
+        target = 9
+        self.assertEqual(output, target)
+
+    def test_third_pattern(self):
+        solution = Solution()
+        output = solution.longestConsecutive(nums = [1,0,1,2])
+        target = 3
+        self.assertEqual(output, target)