From 003d2537795b3dc852b3ce0e622eceb60b46daca Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Sat, 20 Dec 2025 21:45:49 +0900
Subject: [PATCH] baekjoon 20251220

---
 code_study/Baekjoon/python/3046.py   |  1 +
 code_study/Baekjoon/swift/2239.swift | 84 ++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100644 code_study/Baekjoon/python/3046.py
 create mode 100644 code_study/Baekjoon/swift/2239.swift

diff --git a/code_study/Baekjoon/python/3046.py b/code_study/Baekjoon/python/3046.py
new file mode 100644
index 0000000..cd4a721
--- /dev/null
+++ b/code_study/Baekjoon/python/3046.py
@@ -0,0 +1 @@
+print((lambda r1, s : 2*s - r1)(*map(int, input().split())))
\ No newline at end of file
diff --git a/code_study/Baekjoon/swift/2239.swift b/code_study/Baekjoon/swift/2239.swift
new file mode 100644
index 0000000..8c1db4d
--- /dev/null
+++ b/code_study/Baekjoon/swift/2239.swift
@@ -0,0 +1,84 @@
+import Foundation
+
+var rowCheck: [[Bool]] = Array(repeating: Array(repeating: false, count: 10), count: 9)
+var colCheck: [[Bool]] = Array(repeating: Array(repeating: false, count: 10), count: 9)
+var squareCheck: [[Bool]] = Array(repeating: Array(repeating: false, count: 10), count: 9)
+
+let squareArea = {(row: Int, col: Int) -> Int in
+                    return (row/3)*3 + (col/3)
+}
+
+var board: [[Int]] = []
+var emptyAxis: [(Int, Int)] = []
+
+for row in 0..<9 {
+    if let input = readLine(),
+       let line = input.compactMap({Int(String($0))}) as? [Int],
+       line.count == 9
+    {
+        for col in 0..<9 {
+            let num = line[col]
+            
+            if num != 0 {
+                let square = squareArea(row, col)
+                rowCheck[row][num] = true
+                colCheck[col][num] = true
+                squareCheck[square][num] = true
+            }
+            else {
+                emptyAxis.append((row, col))
+            }
+        }
+        
+        board.append(line)
+    }
+}
+
+func isPossible(row: Int, col: Int, num: Int) -> Bool {
+    if rowCheck[row][num] {
+        return false
+    }
+    
+    if colCheck[col][num] {
+        return false
+    }
+    
+    if squareCheck[squareArea(row, col)][num] {
+        return false
+    }
+    
+    return true
+}
+
+func backTracking(_ depth: Int) {
+    if depth == emptyAxis.count {
+        for row in board {
+            for num in row {
+                print(num, terminator: "")
+            }
+            print()
+        }
+        
+        exit(0)
+    }
+    
+    let (row, col) = emptyAxis[depth]
+    
+    for num in 1...9 {
+        if isPossible(row: row, col: col, num: num) {
+            board[row][col] = num
+            rowCheck[row][num] = true
+            colCheck[col][num] = true
+            squareCheck[squareArea(row, col)][num] = true
+            
+            backTracking(depth+1)
+            
+            board[row][col] = 0
+            rowCheck[row][num] = false
+            colCheck[col][num] = false
+            squareCheck[squareArea(row, col)][num] = false
+        }
+    }
+}
+
+backTracking(0)