diff --git a/contains-duplicate/HISEHOONAN.swift b/contains-duplicate/HISEHOONAN.swift
new file mode 100644
index 000000000..c65f5c2cb
--- /dev/null
+++ b/contains-duplicate/HISEHOONAN.swift
@@ -0,0 +1,17 @@
+//
+//  Contains_Duplicate.swift
+//  Algorithm
+//
+//  Created by 안세훈 on 3/31/25.
+//
+
+import Foundation
+
+class Solution {
+    func containsDuplicate(_ nums: [Int]) -> Bool {
+        return nums.count != Set(nums).count
+        //Set : 중복된 값을 갖지 않음.
+        //문제로 주어진 배열의 개수와 중복을 갖지않는 Set연산의 개수의 차이 비교
+        //비교 후 다르다면 true 같다면 false
+    }
+}
diff --git a/house-robber/HISEHOONAN.swift b/house-robber/HISEHOONAN.swift
new file mode 100644
index 000000000..31aa34ca4
--- /dev/null
+++ b/house-robber/HISEHOONAN.swift
@@ -0,0 +1,27 @@
+//
+//  House_Robber .swift
+//  Algorithm
+//
+//  Created by 안세훈 on 3/31/25.
+//
+///https://leetcode.com/problems/house-robber/description/
+
+class Solution {
+    //Dynamic Programming
+    func rob(_ nums: [Int]) -> Int {
+
+        if nums.count == 1 {return nums[0]} //배열이 1개인 경우
+        if nums.count == 2 {return max(nums[0],nums[1])} //배열이 2개인 경우
+        
+        var dp = [nums[0], max(nums[0],nums[1])]
+                //제일 base가 되는 두 값을 찾는게 제일 중요함.
+                //nums[0]은 nums[1]보다 무조건 작아야함.
+        for i in 2..<nums.count{
+            dp.append(max(dp[i-2]+nums[i],dp[i-1]))
+            //dp배열의 i-2번째 배열 + nums의 i번째 배열 vs dp의 i-1번째 배열 중 큰걸 append
+            //
+        }
+        
+        return dp[dp.count-1]
+    }
+}
diff --git a/longest-consecutive-sequence/HISEHOONAN.swift b/longest-consecutive-sequence/HISEHOONAN.swift
new file mode 100644
index 000000000..3a4d33276
--- /dev/null
+++ b/longest-consecutive-sequence/HISEHOONAN.swift
@@ -0,0 +1,31 @@
+//
+//  Longest_Consecutive_Sequence.swift
+//  Algorithm
+//
+//  Created by 안세훈 on 3/31/25.
+//
+
+///https://leetcode.com/problems/longest-consecutive-sequence/
+
+
+class Solution {
+    func longestConsecutive(_ nums: [Int]) -> Int {
+        guard nums.count != 0 else { return 0 }
+
+        var sortednums = Array(Set(nums)).sorted() //중복제거 + 오름차순 정렬
+        var maxcount = 1 //최대 카운드
+        var count = 1 // 연산용 카운트
+
+        for i in 0..<sortednums.count - 1 {
+            if sortednums[i] == sortednums[i+1]-1 {
+                //i번째 정렬된 리스트 와 i+1번째 리스트의 값 - 1이 같을 경우
+                count += 1 //카운트에 1+
+                maxcount = max(maxcount, count) //maxcount는 연산과, max중 큰 것
+            } else {
+                count = 1  //아니면 1로 초기화.
+            }
+        }
+
+        return maxcount
+    }
+}
diff --git a/top-k-frequent-elements/HISEHOONAN.swift b/top-k-frequent-elements/HISEHOONAN.swift
new file mode 100644
index 000000000..f93c27ee4
--- /dev/null
+++ b/top-k-frequent-elements/HISEHOONAN.swift
@@ -0,0 +1,26 @@
+//
+//  Top_K_Frequent_Elements .swift
+//  Algorithm
+//
+//  Created by 안세훈 on 3/31/25.
+//
+
+class Solution {
+    func topKFrequent(_ nums: [Int], _ k: Int) -> [Int] {
+        var dic : [Int : Int] = [:]
+
+        for i in nums {
+            dic[i] = dic[i , default : 0] + 1
+        }
+
+        var sortarray = dic.sorted{$0.value > $1.value}
+        var answer : [Int] = []
+
+        for i in 0..<k{
+            answer.append(sortarray[i].key)
+        }
+        print(sortarray)
+        print(answer)
+        return answer
+    }
+}
diff --git a/two-sum/HISEHOONAN.swift b/two-sum/HISEHOONAN.swift
new file mode 100644
index 000000000..341991440
--- /dev/null
+++ b/two-sum/HISEHOONAN.swift
@@ -0,0 +1,20 @@
+//
+//  Two_Sum.swift
+//  Algorithm
+//
+//  Created by 안세훈 on 3/31/25.
+//
+
+class Solution {
+    func twoSum(_ nums: [Int], _ target: Int) -> [Int] {
+        for i in 0...nums.count-1{
+            for j in i+1...nums.count-1{
+                if nums[i] + nums[j] == target{
+                    return [i,j]
+                }
+            }
+        }
+        return []
+    }
+    //i번째 인덱스의 값과, j번째 인덱스의 값이 target과 같으면 i,j를 리턴
+}