Longest Consecutive Sequence Solution

Author: doh6077

longest-consecutive-sequence/doh6077.py

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+# 배열을 정렬하고 포인터를 두개 사용
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        if not nums:
+            return 0
+        
+        # sort the given list 
+        sorted_nums = sorted(nums)
+    
+        longest = 1
+        curr = 1
+        
+        l, r = 0, 1
+        
+        while r < len(sorted_nums):
+            # case 1: exactly consecutive (x, x+1)
+            if sorted_nums[r] == sorted_nums[l] + 1:
+                curr += 1
+                longest = max(longest, curr)
+                l += 1
+                r += 1
+            
+            # case 2: duplicate (x, x) → ignore, move right pointer
+            elif sorted_nums[r] == sorted_nums[l]:
+                l += 1
+                r += 1
+            
+            # case 3: gap
+            else:
+                curr = 1
+                l = r
+                r += 1
+        
+        return longest