Sync LeetCode submission - Contains Duplicate (python3)

Author: yogeshvar

Leetcode/problems/contains_duplicate/solution.py

@@ -1,4 +1,9 @@
 class Solution:
     def containsDuplicate(self, nums: List[int]) -> bool:
-        s = set(nums)
-        return True if len(s) != len(nums) else False
+        hashset = set()
+
+        for n in nums: 
+            if n in hashset:
+                return True
+            hashset.add(n)
+        return False