Add 2015

2015/Day9.playground/Contents.swift

@@ -0,0 +1,69 @@
+var input: [(from: String, to: String, distance: Int)] = [
+    ("Tristram", "AlphaCentauri", 34),
+    ("Tristram", "Snowdin", 100),
+    ("Tristram", "Tambi", 63),
+    ("Tristram", "Faerun", 108),
+    ("Tristram", "Norrath", 111),
+    ("Tristram", "Straylight", 89),
+    ("Tristram", "Arbre", 132),
+    ("AlphaCentauri", "Snowdin", 4),
+    ("AlphaCentauri", "Tambi", 79),
+    ("AlphaCentauri", "Faerun", 44),
+    ("AlphaCentauri", "Norrath", 147),
+    ("AlphaCentauri", "Straylight", 133),
+    ("AlphaCentauri", "Arbre", 74),
+    ("Snowdin", "Tambi", 105),
+    ("Snowdin", "Faerun", 95),
+    ("Snowdin", "Norrath", 48),
+    ("Snowdin", "Straylight", 88),
+    ("Snowdin", "Arbre", 7),
+    ("Tambi", "Faerun", 68),
+    ("Tambi", "Norrath", 134),
+    ("Tambi", "Straylight", 107),
+    ("Tambi", "Arbre", 40),
+    ("Faerun", "Norrath", 11),
+    ("Faerun", "Straylight", 66),
+    ("Faerun", "Arbre", 144),
+    ("Norrath", "Straylight", 115),
+    ("Norrath", "Arbre", 135),
+    ("Straylight", "Arbre", 127),
+]
+
+var distances: [String: [String: Int]] = input.reduce(into: [:]) { result, input in
+    let (from, to, distance) = input
+
+    result[from, default: [:]][to] = distance
+    result[to, default: [:]][from] = distance
+}
+
+func totalDistance(route: [String]) -> Int {
+    var distance = 0
+    var current = route[0]
+    for place in route.dropFirst() {
+        distance += distances[current]![place]!
+        current = place
+    }
+
+    return distance
+}
+
+func combinations(_ s: Set<String>) -> [[String]] {
+    if s.count <= 2 {
+        return [Array(s)]
+    }
+
+    return s.reduce([]) { result, first in
+        let rest = s.subtracting([first])
+
+        return result + combinations(rest).map { sub in
+            var result = [first]
+            result.append(contentsOf: sub)
+            return result
+        }
+    }
+}
+
+combinations(Set(distances.keys))
+    .map { totalDistance(route: $0) }
+    .max()
+

2015/Day9.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true' importAppTypes='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

2015/Day9.playground/playground.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:">
+   </FileRef>
+</Workspace>