d25

day25/d25p1.swift

@@ -0,0 +1,62 @@
+import Foundation
+
+struct Key : CustomStringConvertible {
+    let pins: [Int]
+    var description: String {
+        return "(" + pins.map(String.init).joined(separator: ",") + ")"
+    }
+    init(_ block: ArraySlice<[Character]>) {
+        var pins: [Int] = [0, 0, 0, 0, 0]
+        ((block.startIndex+1)..<(block.endIndex-1)).forEach { i in
+            for j in 0..<5 {
+                if pins[j] == 0 && block[i][j] == "#" {
+                    pins[j] = 6 - (i - block.startIndex)
+                }
+            }
+        }
+        self.pins = pins
+    }
+}
+
+struct Lock : CustomStringConvertible { 
+    let pins: [Int]
+    var description: String {
+        return "(" + pins.map(String.init).joined(separator: ",") + ")"
+    }
+    init(_ block: ArraySlice<[Character]>) {
+        var pins: [Int] = [0, 0, 0, 0, 0]
+        ((block.startIndex+1)..<(block.endIndex-1)).reversed().forEach { i in
+            for j in 0..<5 {
+                if pins[j] == 0 && block[i][j] == "#" {
+                    pins[j] = i - block.startIndex
+                }
+            }
+        }
+        self.pins = pins
+    }
+}
+
+func readInput(_ filePath: String) throws -> ([Lock], [Key]) {
+    let content = try String(contentsOfFile: filePath, encoding: .ascii)
+    let lines = content.split(separator: "\n", omittingEmptySubsequences: false)
+    var locks: [Lock] = []
+    var keys: [Key] = []
+    lines.map(Array.init).split(separator: []).forEach { block in
+        if block[block.startIndex][0] == "#" {
+            locks.append(Lock(block))
+        } else {
+            keys.append(Key(block))
+        }
+    }
+    return (locks, keys)
+}
+
+let (locks, keys) = try readInput(CommandLine.arguments[1])
+var answer = 0
+for lock in locks {
+    for key in keys {
+        answer += zip(lock.pins, key.pins).contains { $0 + $1 > 5 } ? 0 : 1
+    }
+}
+print(answer)
+

day25/test.txt

@@ -0,0 +1,39 @@
+#####
+.####
+.####
+.####
+.#.#.
+.#...
+.....
+
+#####
+##.##
+.#.##
+...##
+...#.
+...#.
+.....
+
+.....
+#....
+#....
+#...#
+#.#.#
+#.###
+#####
+
+.....
+.....
+#.#..
+###..
+###.#
+###.#
+#####
+
+.....
+.....
+.....
+#....
+#.#..
+#.#.#
+#####