Initial commit

common/LoadData.swift

@@ -0,0 +1,30 @@
+import Foundation
+
+func loadData(day: Int) -> String {
+    guard let session = getenv("SESSION") else {
+        fatalError("Missing session env var")
+    }
+
+    var request = URLRequest(url: URL(string: "https://adventofcode.com/2020/day/\(day)/input")!)
+    request.setValue("session=\(String(cString: session))", forHTTPHeaderField: "Cookie")
+
+    var result: String? = nil
+
+    let group = DispatchGroup()
+
+    group.enter()
+    let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
+        guard error == nil, let data = data, let response = response as? HTTPURLResponse, response.statusCode == 200 else {
+            fatalError("Cannot get input from server")
+        }
+
+        result = String(data: data, encoding: .utf8)
+        group.leave()
+    }
+
+    task.resume()
+
+    group.wait()
+
+    return result!
+}

common/Scanner+Extensions.swift

@@ -0,0 +1,26 @@
+import Foundation
+
+extension Scanner {
+    @discardableResult
+    func string(_ string: String) -> Bool {
+        return scanString(string) != nil
+    }
+
+    func integers() -> [Int]? {
+        var numbers: [Int] = []
+        while !isAtEnd {
+            guard let num = scanInt() else { return nil }
+            numbers.append(num)
+        }
+        return numbers
+    }
+}
+
+
+extension String {
+    func lines() -> [String] {
+        var result: [String] = []
+        enumerateLines { line, _ in result.append(line) }
+        return result
+    }
+}