From b689915f87094a4be98219bba9371842e710c451 Mon Sep 17 00:00:00 2001
From: JungHm <taggma12@gmail.com>
Date: Sun, 13 Apr 2025 16:07:18 +0900
Subject: [PATCH 1/3] solve: valid palindrome

---
 valid-palindrome/JustHm.swift | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 valid-palindrome/JustHm.swift

diff --git a/valid-palindrome/JustHm.swift b/valid-palindrome/JustHm.swift
new file mode 100644
index 000000000..930ebb97d
--- /dev/null
+++ b/valid-palindrome/JustHm.swift
@@ -0,0 +1,11 @@
+class Solution {
+    func isPalindrome(_ s: String) -> Bool {
+        let answer = s.lowercased().filter {
+            if $0.isLetter || $0.isNumber {
+                return true
+            }
+            return false
+        }
+        return answer == String(answer.reversed()) ? true : false
+    }
+}

From 8448f5ba1592c0b1a2b144406a393f0b15dac095 Mon Sep 17 00:00:00 2001
From: JungHm <taggma12@gmail.com>
Date: Mon, 14 Apr 2025 11:02:08 +0900
Subject: [PATCH 2/3] solve: number of 1 bits

---
 number-of-1-bits/JustHm.swift | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 number-of-1-bits/JustHm.swift

diff --git a/number-of-1-bits/JustHm.swift b/number-of-1-bits/JustHm.swift
new file mode 100644
index 000000000..198e7e592
--- /dev/null
+++ b/number-of-1-bits/JustHm.swift
@@ -0,0 +1,21 @@
+// time: O(n)
+class Solution {
+    func hammingWeight(_ n: Int) -> Int {
+        return String(n, radix: 2).filter{$0 == "1"}.count
+    }
+}
+// time: O(1), space: O(1)
+class AnotherSolution {
+    func hammingWeight(_ n: Int) -> Int {
+        var count = 0
+        var num = n
+        // 최대 32비트이기 때문에 반복을 32번 돌며 비트를 순회함
+        for _ in 0..<32 {
+            if num & 1 == 1 { // 가장 오른쪽 비트만 가져와 1인지 확인함
+                count += 1 // 비트가 1이면 count 증가
+            }
+            num >>= 1 // 오른쪽으로 1비트 이동
+        }
+        return count
+    }
+}

From ae6f8d9a74068d7a8b2e0f17438206f128809a18 Mon Sep 17 00:00:00 2001
From: JungHm <taggma12@gmail.com>
Date: Thu, 17 Apr 2025 00:18:58 +0900
Subject: [PATCH 3/3] solve: combination sum

---
 combination-sum/JustHm.swift | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 combination-sum/JustHm.swift

diff --git a/combination-sum/JustHm.swift b/combination-sum/JustHm.swift
new file mode 100644
index 000000000..f9474bd0d
--- /dev/null
+++ b/combination-sum/JustHm.swift
@@ -0,0 +1,26 @@
+// 해설 참조..
+class Solution {
+    func combinationSum(_ candidates: [Int], _ target: Int) -> [[Int]] {
+        // 우선 답변용, 조합 찾기용 변수 생성
+        var answer = [[Int]]()
+        var nums = [Int]()
+        // 백트래킹 기법으로 로직 작성,
+        // 현재 원소 위치와 합했을때의 값을 인자로 받음
+        func backtracking(start: Int, total: Int) {
+            // 전처리
+            if total > target { return } // total이 target 보다 크면 조합X
+            else if total == target { return answer.append(nums) } // 같으면 답변용 변수에 추가
+            
+            // 시작 부분부터 값을 하나씩 더해서 재귀로 돌려봄
+            for index in start..<candidates.count {
+                let temp = candidates[index]
+                nums.append(temp) //먼저 선택된 원소를 조합 배열에 추가
+                backtracking(start: index, total: total + temp) // 현재 선택된 원소의 인덱스와 총 합을 인자로 함수 호출
+                nums.removeLast() // 조합찾기가 끝나면 종료
+            }
+        }
+        // 초기부터 시작함
+        backtracking(start: 0, total: 0)
+        return answer
+    }
+}