Some optimisations

Sources/17/17.swift

@@ -30,7 +30,7 @@ struct Area {
     }
     
     func overshot(point: Point) -> Bool {
-        point.x > botRight.x || point.y < botRight.y
+        point.y < botRight.y || point.x > botRight.x
     }
 }
 
@@ -41,18 +41,11 @@ struct Probe {
     mutating func move() {
         position.x += velocity.x
         position.y += velocity.y
-        var dX: Int
-        switch velocity.x {
-        case _ where velocity.x < 0:
-            dX = 1
-        case 0:
-            dX = 0
-        case _ where velocity.x > 0:
-            dX = -1
-        default:
-            fatalError()
+        if velocity.x < 0 {
+            velocity.x += 1
+        } else if velocity.x > 0 {
+            velocity.x -= 1
         }
-        velocity.x += dX
         velocity.y -= 1
     }
 }
@@ -74,7 +67,8 @@ class Day17: Runnable {
         let area = Area(x: parts.first!, y: parts.last!)
         
         var maxY = Int.min
-        var found = Set<Point>()
+        var found = [Point]()
+        found.reserveCapacity(3000)
         for x in 0...500 {
             for y in -500...500 {
                 let velocity = Point(x: x, y: y)
@@ -89,13 +83,13 @@ class Day17: Runnable {
                         if maxYCurrent > maxY {
                             maxY = maxYCurrent
                         }
-                        found.insert(velocity)
+                        found.append(velocity)
                         break
                     }
                 } while !area.overshot(point: probe.position)
             }
         }
         print(maxY)
-        print(found.count)
+        print(Set(found).count)
     }
 }