From e62a0af0ad7b9431d97d9d0ae6384b02436e07f1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EB=91=90=EB=A6=AC?= <kdle_@naver.com>
Date: Sat, 19 Apr 2025 15:12:43 +0900
Subject: [PATCH 1/5] Solution Valid Palindrome

---
 valid-palindrome/doitduri.swift | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 valid-palindrome/doitduri.swift

diff --git a/valid-palindrome/doitduri.swift b/valid-palindrome/doitduri.swift
new file mode 100644
index 000000000..b9654768f
--- /dev/null
+++ b/valid-palindrome/doitduri.swift
@@ -0,0 +1,6 @@
+class Solution {
+    func isPalindrome(_ s: String) -> Bool {
+        let strings = s.filter { $0.isLetter || $0.isNumber }.lowercased()
+        return String(strings.reversed()) == strings
+    }
+}

From a048c17fd801b55b6de798420b26a35c31299f7a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EB=91=90=EB=A6=AC?= <kdle_@naver.com>
Date: Sat, 19 Apr 2025 15:26:46 +0900
Subject: [PATCH 2/5] Solution Number of 1 bits

---
 number-of-1-bits/doitduri.swift | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 number-of-1-bits/doitduri.swift

diff --git a/number-of-1-bits/doitduri.swift b/number-of-1-bits/doitduri.swift
new file mode 100644
index 000000000..036263d5f
--- /dev/null
+++ b/number-of-1-bits/doitduri.swift
@@ -0,0 +1,6 @@
+class Solution {
+    func hammingWeight(_ n: Int) -> Int {
+        let bitString = String(n, radix: 2)
+        return bitString.filter { $0 == "1" }.count
+    }
+}

From 927999074286edbfe03c6e3f0c73e575fe116a7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EB=91=90=EB=A6=AC?= <kdle_@naver.com>
Date: Sat, 19 Apr 2025 15:40:36 +0900
Subject: [PATCH 3/5] Solution Combination sum

---
 combination-sum/doitduri.swift | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 combination-sum/doitduri.swift

diff --git a/combination-sum/doitduri.swift b/combination-sum/doitduri.swift
new file mode 100644
index 000000000..56861acfb
--- /dev/null
+++ b/combination-sum/doitduri.swift
@@ -0,0 +1,31 @@
+class Solution {
+    func combinationSum(_ candidates: [Int], _ target: Int) -> [[Int]] {
+        if candidates.filter { $0 > target }.count == candidates.count {
+            return []
+        }
+        
+        var result: [[Int]] = []
+        var current: [Int] = []
+        
+        func backtrack(_ start: Int, _ remain: Int) {
+            if remain == 0 {
+                result.append(current)
+                return
+            }
+            
+            if remain < 0 {
+                return
+            }
+            
+            for i in start..<candidates.count {
+                current.append(candidates[i])
+                backtrack(i, remain - candidates[i])
+                current.removeLast()
+            }
+        }
+        
+        backtrack(0, target)
+        
+        return result
+    }
+}

From a3e09bd94fb72c0464d54c8f87d5257e2597074f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EB=91=90=EB=A6=AC?= <kdle_@naver.com>
Date: Sat, 19 Apr 2025 16:45:04 +0900
Subject: [PATCH 4/5] Solution Decode ways

---
 decode-ways/doitduri.swift | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 decode-ways/doitduri.swift

diff --git a/decode-ways/doitduri.swift b/decode-ways/doitduri.swift
new file mode 100644
index 000000000..733f2e180
--- /dev/null
+++ b/decode-ways/doitduri.swift
@@ -0,0 +1,31 @@
+class Solution {
+    func numDecodings(_ s: String) -> Int {
+         if s.first == "0" {
+            return 0
+        }
+
+        if s.count == 1 {
+            return 1
+        }
+
+        var tables = Array(repeating: 0, count: s.count+1)
+        let chars = Array(s)
+        tables[0] = 1
+        tables[1] = 1
+        
+        for i in 2...s.count {
+            if chars[i-1] != "0" {
+                tables[i] += tables[i-1]
+            }
+
+            if let twoDigit = Int(String(chars[i-2...i-1])) {
+                if 10 <= twoDigit && twoDigit <= 26 {
+                    tables[i] += tables[i-2]
+                }
+            }
+            
+        }
+        
+        return tables[s.count]
+    }
+}

From cdd182611f1024875cfefa57d1ef67f0b8bf6c3b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EB=91=90=EB=A6=AC?= <kdle_@naver.com>
Date: Sat, 19 Apr 2025 18:27:43 +0900
Subject: [PATCH 5/5] Solution Maximum subarray

---
 maximum-subarray/doitduri.swift | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 maximum-subarray/doitduri.swift

diff --git a/maximum-subarray/doitduri.swift b/maximum-subarray/doitduri.swift
new file mode 100644
index 000000000..34de6df0b
--- /dev/null
+++ b/maximum-subarray/doitduri.swift
@@ -0,0 +1,12 @@
+class Solution {
+    func maxSubArray(_ nums: [Int]) -> Int {
+        var currentSum = nums[0]
+        var maxSum = nums[0]
+        
+        for i in 1..<nums.count {
+            currentSum = max(nums[i], currentSum + nums[i])
+            maxSum = max(maxSum, currentSum)
+        }
+        return maxSum
+    }
+}