Add solution for Longest Consecutive Sequence

Author: jamiebase

longest-consecutive-sequence/gcount85.py

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+"""
+# Intuition
+Sort array first, then compare every element with its previous one
+while counting consecutive ones.
+
+# Approach
+1. sort
+2. initiate variables: max_count, current_count, previous_element_idx
+3. for n in nums:
+    3-1. if n is nums[prev] + 1: current_count++
+        elif n is smaller or bigger than nums[prev] + 1:
+            update max_count and initiate current_count
+    3-2. increase previous element index
+4. return max_count
+
+# Complexity
+- Time complexity: O(N)
+
+- Space complexity: O(1)
+"""
+
+
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        nums.sort()
+        max_count = 0
+        count = 1
+        prev = 0
+        for n in nums[1:]:
+            if n == nums[prev] + 1:
+                count += 1
+            elif n < nums[prev] or n > nums[prev] + 1:
+                max_count = max(count, max_count)
+                count = 1
+            prev += 1
+        return max(count, max_count) if len(nums) else 0