d02

day02/d02p1.swift

@@ -0,0 +1,21 @@
+import Foundation
+
+func readInput(filePath: String) -> [[Int?]]? {
+    let content =  try? String(contentsOfFile: filePath, encoding: .ascii)
+    let lines = content?.split(separator: "\n")
+    return lines?.map { $0.split(separator: " ").map { Int($0) } }
+}
+
+func check(_ report: [Int?]) -> Bool? {
+    if report.contains(nil) {
+        return nil
+    }
+    let diffs = zip(report.dropFirst(), report).map { $0.0! - $0.1! }
+    return diffs.allSatisfy { abs($0) >= 1 }
+        && diffs.allSatisfy { abs($0) <= 3 }
+        && (diffs.allSatisfy { $0 > 0 } || diffs.allSatisfy { 0 > $0 })
+}
+
+let reports = readInput(filePath: CommandLine.arguments[1])
+let answer = reports!.compactMap(check).reduce(0, {n, x in x ? n+1 : n})
+print(answer)