Attempt a more primitive variant

Author: mnvr

15.az.swift

@@ -0,0 +1,44 @@
+var s = 0
+var boxes: [[[String]]] = Array(repeating: [], count: 256)
+while let line = readLine() {
+    for word in line.split(separator: ",") {
+        let splits = word.split { $0 == "=" || $0 == "-" } .map { String($0) }
+        let bi = hash(splits[0])
+        s += hash(String(word))
+        boxes[bi] = modify(box: boxes[bi], splits, bi)
+    }
+}
+print(s, power(boxes))
+
+func hash(_ s: String) -> Int {
+    return s.utf8.reduce(0) { ($0 + Int($1)) * 17 % 256 }
+}
+
+func modify(box: [[String]], _ splits: [String], _ bi: Int) -> [[String]] {
+    var box = box
+    var label = splits.first
+    if splits.count == 1 {
+        box.removeAll { $0.first == label }
+    } else {
+        for (i, l) in box.enumerated() {
+            if l.first == label {
+                box[i] = splits
+                label = nil
+            }
+        }
+        if let _ = label {
+            box.append(splits)
+        }
+    }
+    return box
+}
+
+func power(_ boxes: [[[String]]]) -> Int {
+    var s = 0
+    for (i, box) in boxes.enumerated() {
+        for (j, lens) in box.enumerated() {
+            s += (i + 1) * (j + 1) * Int(lens.last!, radix: 10)!
+        }
+    }
+    return s
+}

15.swift

@@ -46,7 +46,7 @@ func decode<S: StringProtocol>(_ s: S) -> Step {
     if splits.count == 1 {
         return Step(op: .remove(String(splits[0])), box: box)
     }
-    let lens = Lens(label: splits[0], length: splits[1]);
+    let lens = Lens(label: splits[0], length: splits[1])
     return Step(op: .replace(lens), box: box)
 }