Add solution for Contains Duplicate

Author: jamiebase

contains-duplicate/gcount85.py

@@ -0,0 +1,9 @@
+# Approach : De-duplicate using Set
+# Complexity: O(n)
+# Space complexity: O(n)
+
+
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        dedup = set(nums)
+        return len(dedup) != len(nums)