day1 part2

day01/Sources/day01/day01.swift

@@ -5,31 +5,58 @@
 struct day01 {
     static func parseInput(_ input: String) -> [(Direction, Int)] {
         return input.split(whereSeparator: \.isNewline)
-            .map({ line in
-                return (Direction(line.first!), Int(line.dropFirst())!)
-            })
-
+        .map({ line in
+            return (Direction(line.first!), Int(line.dropFirst())!)
+        })
     }
 
     static func part1(_ input: [(Direction, Int)]) {
         var cur = 50
         var count = 0
         for (dir, num) in input {
-            let last = cur
             cur = switch dir {
                 case .Left: (cur - num) % 100
                 case .Right: (cur + num) % 100
             }
             if (cur < 0) { cur += 100 }
-            print(last, cur, dir, num)
             if (cur == 0) { count += 1 }
         }
         print("Part 1: \(count)")
     }
 
+    static func part2(_ input: [(Direction, Int)]) {
+        var cur = 50
+        var count = 0
+        for (dir, num) in input {
+            let start = cur
+            let fullCycles = num - (num % 100)
+            count += fullCycles / 100
+
+            cur = switch dir {
+                case .Left: (cur - num) % 100
+                case .Right: (cur + num) % 100
+            }
+            if (cur < 0) { cur += 100 }
+
+            switch dir {
+                case .Left:
+                    if (start - (num % 100)) < 0 && start != 0 {
+                        count += 1
+                    }
+                case .Right:
+                    if (start + (num % 100)) >= 100 && start != 0 && cur != 0 {
+                        count += 1
+                    }
+            }
+            if (cur == 0) { count += 1 }
+        }
+        print("Part 2: \(count)")
+    }
+
     static func main() {
         let parsed = parseInput(realInput)
         part1(parsed)
+        part2(parsed)
     }
 }