From 507cba2f3b913191ddd3e5dc78566256e1e59357 Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Tue, 27 Jan 2026 20:55:03 +0900
Subject: [PATCH] baekjoon 20260127

---
 code_study/Baekjoon/c/10808.c          | 17 ++++++
 code_study/Baekjoon/swift/1005_2.swift | 80 ++++++++++++++++++++++++++
 code_study/Baekjoon/swift/7453.swift   | 65 +++++++++++++++++++++
 3 files changed, 162 insertions(+)
 create mode 100644 code_study/Baekjoon/c/10808.c
 create mode 100644 code_study/Baekjoon/swift/1005_2.swift
 create mode 100644 code_study/Baekjoon/swift/7453.swift

diff --git a/code_study/Baekjoon/c/10808.c b/code_study/Baekjoon/c/10808.c
new file mode 100644
index 0000000..772188b
--- /dev/null
+++ b/code_study/Baekjoon/c/10808.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int count[26];
+
+int main() {
+    char s[101];
+    scanf("%s", s);
+
+    int i=0;
+    while(s[i] !='\0') {
+        count[s[i++] - 'a']++;
+    }
+
+    for(int j=0; j<26; j++) printf("%d ",count[j]);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/swift/1005_2.swift b/code_study/Baekjoon/swift/1005_2.swift
new file mode 100644
index 0000000..941d00a
--- /dev/null
+++ b/code_study/Baekjoon/swift/1005_2.swift
@@ -0,0 +1,80 @@
+import Foundation
+
+final class FileIO {
+    private let buffer:[UInt8]
+    private var index: Int = 0
+
+    init(fileHandle: FileHandle = FileHandle.standardInput) {
+        
+        buffer = Array(try! fileHandle.readToEnd()!) + [UInt8(0)]
+    }
+
+    @inline(__always) private func read() -> UInt8 {
+        defer { index += 1 }
+        return buffer[index]
+    }
+
+    @inline(__always) func readInt() -> Int {
+        var sum = 0
+        var now = read()
+        var isPositive = true
+
+        while now == 10 || now == 32 { now = read() }
+        if now == 45 { isPositive = false; now = read() }
+
+        while now >= 48, now <= 57 {
+            sum = sum * 10 + Int(now-48)
+            now = read()
+        }
+
+        return sum * (isPositive ? 1 : -1)
+    }
+}
+
+let input = FileIO()
+var ans: [String] = []
+
+func solve() -> String {
+    let (N, K) = (input.readInt(), input.readInt())
+    
+    var build_time: [Int] = [0]
+    for _ in 0..<N {
+        build_time.append(input.readInt())
+    }
+    
+    var pre_build_info: [[Int]] = Array(repeating: [], count: N+1)
+    for _ in 0..<K {
+        let (X, Y) = (input.readInt(), input.readInt())
+        pre_build_info[Y].append(X)
+    }
+    
+    let W = input.readInt()
+    
+    var dp: [Int] = Array(repeating: -1, count: N+1)
+    
+    func build(_ n: Int) -> Int {
+        if dp[n] == -1 {
+            var total_time = 0
+            for prev in pre_build_info[n] {
+                total_time = max(total_time, build(prev))
+            }
+            dp[n] = total_time + build_time[n]
+        }
+        
+        return dp[n]
+    }
+    
+    return String(build(W))
+}
+
+func main() {
+    let T = input.readInt()
+    
+    for _ in 0..<T {
+        ans.append(solve())
+    }
+    
+    print(ans.joined(separator: "\n"))
+}
+
+main()
diff --git a/code_study/Baekjoon/swift/7453.swift b/code_study/Baekjoon/swift/7453.swift
new file mode 100644
index 0000000..a0d05e5
--- /dev/null
+++ b/code_study/Baekjoon/swift/7453.swift
@@ -0,0 +1,65 @@
+func solve() {
+    guard let n = Int(readLine() ?? "") else { return }
+    var A: [Int] = [Int]()
+    var B: [Int] = [Int]()
+    var C: [Int] = [Int]()
+    var D: [Int] = [Int]()
+    
+    for _ in 0..<n {
+        guard let input = readLine() else { break }
+        let ABCD = input.split(separator: " ").compactMap{Int($0)}
+        
+        guard ABCD.count == 4 else { break }
+        A.append(ABCD[0])
+        B.append(ABCD[1])
+        C.append(ABCD[2])
+        D.append(ABCD[3])
+    }
+    
+    var AB: [Int] = [Int]()
+    var CD: [Int] = [Int]()
+    
+    for i in 0..<n {
+        for j in 0..<n {
+            AB.append(A[i] + B[j])
+            CD.append(C[i] + D[j])
+        }
+    }
+    
+    AB.sort()
+    CD.sort(by: >)
+    
+    var (pAB, pCD) = (0, 0)
+    let (nAB, nCD) = (AB.count, CD.count)
+    var ans = 0
+    
+    while pAB < nAB && pCD < nCD {
+        let (ab, cd) = (AB[pAB], CD[pCD])
+        
+        if ab + cd > 0 {
+            pCD += 1
+        }
+        else if ab + cd < 0 {
+            pAB += 1
+        }
+        else {
+            var countAB = 0
+            while pAB < nAB && ab == AB[pAB] {
+                pAB += 1
+                countAB += 1
+            }
+            
+            var countCD = 0
+            while pCD < nCD && cd == CD[pCD] {
+                pCD += 1
+                countCD += 1
+            }
+            
+            ans += countAB * countCD
+        }
+    }
+    
+    print(ans)
+}
+
+solve()