diff --git a/contains-duplicate/HYUNAHKO.py b/contains-duplicate/HYUNAHKO.py
new file mode 100644
index 000000000..6a11d6a03
--- /dev/null
+++ b/contains-duplicate/HYUNAHKO.py
@@ -0,0 +1,11 @@
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        if len(nums) >= 1 and len(nums) <= 100000:
+            for i in range(0, len(nums)):
+                src = nums[i]
+                for j in range(i+1, len(nums)):
+                    if src == nums[j]:
+                        return True
+            return False
+        return False
+   
diff --git a/top-k-frequent-elements/HYUNAHKO.py b/top-k-frequent-elements/HYUNAHKO.py
new file mode 100644
index 000000000..0144392e3
--- /dev/null
+++ b/top-k-frequent-elements/HYUNAHKO.py
@@ -0,0 +1,14 @@
+class Solution:
+    def topKFrequent(self, nums: List[int], k: int) -> List[int]:
+        value_dict = {}
+        
+        for num in nums:
+            if num in value_dict:
+                value_dict[num] += 1
+            else:
+                value_dict[num] = 1
+        
+        sorted_items = sorted(value_dict.items(), key=lambda x: x[1], reverse=True)
+        
+        return [key for key, value in sorted_items[:k]]
+    
diff --git a/two-sum/HYUNAHKO.py b/two-sum/HYUNAHKO.py
new file mode 100644
index 000000000..8c0740f28
--- /dev/null
+++ b/two-sum/HYUNAHKO.py
@@ -0,0 +1,13 @@
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        result = []
+        if len(nums) >= 2 and len(nums) <= 1e4:
+            for idx1, i in enumerate(nums):
+                num1 = i
+                for idx2 in range(idx1+1, len(nums)):
+                    num2 = nums[idx2]
+                    if ((num1 + num2) == target):
+                        result.append(idx1)
+                        result.append(idx2)
+                        return result
+