diff --git a/contains-duplicate/JiHyeonSu.py b/contains-duplicate/JiHyeonSu.py
new file mode 100644
index 000000000..707ba5593
--- /dev/null
+++ b/contains-duplicate/JiHyeonSu.py
@@ -0,0 +1,5 @@
+# 중복제거 후 길이 확인 문제
+# 시간복잡도 및 공간복잡도 O(n)
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        return len(nums) != len(set(nums))
diff --git a/two-sum/JiHyeonSu.py b/two-sum/JiHyeonSu.py
new file mode 100644
index 000000000..a136ade82
--- /dev/null
+++ b/two-sum/JiHyeonSu.py
@@ -0,0 +1,11 @@
+# 해시맵을 활용한 두 수의 합 구현
+# 시간복잡도 및 공간복잡도 O(n)
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        n_map = {}
+
+        for i, num in enumerate(nums):
+            diff = target - num
+            if diff in n_map:
+                return [n_map[diff], i]
+            n_map[num] = i