Solved 2023 day 4 part 2 in Swift

Author: orhtej2

.vscode/launch.json

@@ -241,6 +241,36 @@
             "name": "Release day04 (2023\\swift\\04)",
             "program": "${workspaceFolder:adventofcode}\\2023\\swift\\04\\.build\\release\\day04.exe",
             "preLaunchTask": "swift: Build Release day04 (2023\\swift\\04)"
+        },
+        {
+            "type": "swift-lldb",
+            "request": "launch",
+            "sourceLanguages": [
+                "swift"
+            ],
+            "args": [
+                "--input",
+                "input.txt"
+            ],
+            "cwd": "${workspaceFolder:adventofcode}\\2023\\swift\\04",
+            "name": "Debug day04b (2023\\swift\\04)",
+            "program": "${workspaceFolder:adventofcode}\\2023\\swift\\04\\.build\\debug\\day04b.exe",
+            "preLaunchTask": "swift: Build Debug day04b (2023\\swift\\04)"
+        },
+        {
+            "type": "swift-lldb",
+            "request": "launch",
+            "sourceLanguages": [
+                "swift"
+            ],
+            "args": [
+                "--input",
+                "input.txt"
+            ],
+            "cwd": "${workspaceFolder:adventofcode}\\2023\\swift\\04",
+            "name": "Release day04b (2023\\swift\\04)",
+            "program": "${workspaceFolder:adventofcode}\\2023\\swift\\04\\.build\\release\\day04b.exe",
+            "preLaunchTask": "swift: Build Release day04b (2023\\swift\\04)"
         }
     ]
 }

2023/swift/04/Package.swift

@@ -18,5 +18,12 @@ let package = Package(
             ],
             path: "Sources/a"
         ),
+        .executableTarget(
+            name: "day04b",
+            dependencies: [
+                .product(name: "ArgumentParser", package: "swift-argument-parser"),
+            ],
+            path: "Sources/b"
+        ),
     ]
 )

2023/swift/04/Sources/b/main.swift

@@ -0,0 +1,45 @@
+import ArgumentParser
+import Foundation
+
+struct Card {
+  var count = 1
+  var score = 0
+}
+
+@main
+struct Day04b: ParsableCommand {
+  @Option(help: "Specify the input")
+  public var input: String
+
+  func numbers(fromString: String) -> [Int] {
+    return fromString.components(separatedBy: " ").compactMap { Int($0) }
+  }
+  public func run() throws {
+    guard let filecontent = try? String(contentsOfFile: input, encoding: .utf8)
+    else {
+        print("Failed to open file \(input)")
+        return
+    }
+    var cards = [Int: Card]()
+    for line in filecontent.components(separatedBy: .newlines) {
+        let split = line.components(separatedBy: [":", "|"])
+        let card = Int(split[0].substring(from: 4).trimmingCharacters(in: [" "]))!
+        let winning = Set<Int>(numbers(fromString: split[1]))
+        let chosen = Set<Int>(numbers(fromString: split[2]))
+        let winningCount = winning.intersection(chosen).count
+        cards[card] = Card(count: 1, score: winningCount)
+    }
+
+    var result = 0
+    for card in cards.keys.sorted() {
+      let c = cards[card]!
+      result += c.count
+      if c.score > 0 {
+        for i in 1...c.score {
+          cards[card + i]!.count += c.count
+        }
+      }
+    }
+    print(result)
+  }
+}