10b

Sources/10/10.swift

@@ -20,28 +20,40 @@ struct Day10: Runnable {
             //.map { line in line.map { $0.wholeNumberValue! } }
         var s = Deque<String.Element>()
         var illegalCharacters = [String.Element]()
+        var autocompleteScores = [Int]()
         for (lineNumber, line) in lines.enumerated() {
+            s = Deque<String.Element>()
+            var isIllegalLine = false
             for char in line {
                 if char.isClosing {
-                    if let popped = s.popFirst() {
+                    guard let popped = s.popFirst() else {
-                        if let shouldBeClosedBy = popped.closedBy {
+                        fatalError()
-                            if shouldBeClosedBy == char {
-                                continue // Valid chunk
-                            }
-                            print("Line: \(lineNumber): Expected \(shouldBeClosedBy), but found \(char) instead")
-                            illegalCharacters.append(char)
-                            break
-                        } else {
-                            print("\(popped) should be an opening character, but cannot find a fitting closing char. Line: \(lineNumber+1), char: \(char)")
-                        }
-                    } else {
-                        print("Found closing character \(char), but empty list!")
                     }
+                    guard let shouldBeClosedBy = popped.closedBy else {
+                        fatalError()
+                    }
+                    if shouldBeClosedBy == char {
+                        continue // Valid chunk
+                    }
+                    //print("Line: \(lineNumber): Expected \(shouldBeClosedBy), but found \(char) instead")
+                    illegalCharacters.append(char)
+                    isIllegalLine = true
+                    break
                 }
                 s.prepend(char)
             }
+            if !isIllegalLine {
+                var lineScore = 0
+                s.reverse()
+                while let last = s.popLast() {
+                    let charValue = last.closedBy!.autocompleteScore!
+                    lineScore = lineScore * 5 + charValue
+                }
+                autocompleteScores.append(lineScore)
+            }
         }
         print(illegalCharacters.map{$0.score!}.reduce(0,+))
+        print(autocompleteScores.sorted()[autocompleteScores.count / 2])
     }
     
     
@@ -78,4 +90,19 @@ extension String.Element {
             return nil
         }
     }
+    
+    var autocompleteScore: Int? {
+        switch self {
+        case ")":
+            return 1
+        case "]":
+            return 2
+        case "}":
+            return 3
+        case ">":
+            return 4
+        default:
+            return nil
+        }
+    }
 }