diff --git a/contains-duplicate/njngwn.py b/contains-duplicate/njngwn.py
new file mode 100644
index 0000000000..68b39c5eba
--- /dev/null
+++ b/contains-duplicate/njngwn.py
@@ -0,0 +1,11 @@
+class Solution:
+    # Time Complexity: O(nlogn), n: len(nums)
+    # Space Complexity: O(1)
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        nums.sort()  # O(nlogn)
+
+        for i in range(len(nums)):
+            if i > 0 and nums[i] == nums[i - 1]:
+                return True
+
+        return False
diff --git a/two-sum/njngwn.py b/two-sum/njngwn.py
new file mode 100644
index 0000000000..68b39c5eba
--- /dev/null
+++ b/two-sum/njngwn.py
@@ -0,0 +1,11 @@
+class Solution:
+    # Time Complexity: O(nlogn), n: len(nums)
+    # Space Complexity: O(1)
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        nums.sort()  # O(nlogn)
+
+        for i in range(len(nums)):
+            if i > 0 and nums[i] == nums[i - 1]:
+                return True
+
+        return False