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sim642sim642
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Clean up 2024 day 14
1 parent fcb53f4 commit 9b2acce

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2 files changed

+145
-14
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2 files changed

+145
-14
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‎src/main/scala/eu/sim642/adventofcode2024/Day14.scala‎

Lines changed: 32 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -9,28 +9,44 @@ object Day14 {
99
// copied from 2021 day 25
1010
extension (pos: Pos) {
1111
def %+(other: Pos): Pos = Pos(pos.x %+ other.x, pos.y %+ other.y)
12+
infix def compareTo(other: Pos): Pos = Pos(pos.x `compareTo` other.x, pos.y `compareTo` other.y)
13+
def sign: Pos = Pos(pos.x.sign, pos.y.sign)
1214
}
1315

1416
case class Robot(pos: Pos, velocity: Pos) {
17+
def step(roomSize: Pos): Robot = Robot((pos + velocity) %+ roomSize, velocity)
1518
def step(t: Int, roomSize: Pos): Robot = Robot((pos + t *: velocity) %+ roomSize, velocity)
1619
}
1720

18-
def safetyFactor(robots: Seq[Robot], roomSize: Pos = Pos(101, 103)): Int = {
21+
val inputRoomSize: Pos = Pos(101, 103)
22+
23+
def safetyFactor(robots: Seq[Robot], roomSize: Pos = inputRoomSize): Int = {
1924
val newRobots = robots.map(_.step(100, roomSize))
20-
//newRobots.foreach(println)
2125
val roomMiddle = Pos(roomSize.x / 2, roomSize.y / 2)
22-
//println(roomMiddle)
23-
//val quadrants0 = newRobots.groupBy(robot => (robot.pos.x.compare(roomMiddle.x), robot.pos.y.compare(roomMiddle.y))).withDefaultValue(0)
24-
//quadrants0.foreach(println)
25-
val quadrants = newRobots.groupCount(robot => (robot.pos.x.compare(roomMiddle.x), robot.pos.y.compare(roomMiddle.y))).withDefaultValue(0)
26-
quadrants((1, 1)) * quadrants((-1, 1)) * quadrants((1, -1)) * quadrants((-1, -1))
26+
val quadrants = newRobots.groupCount(robot =>
27+
(robot.pos `compareTo` roomMiddle).sign // use .sign to clamp to -1, 0, 1
28+
).withDefaultValue(0)
29+
Pos.diagonalOffsets.map(quadrants).product
2730
}
2831

29-
def findEasterEgg(robots: Seq[Robot], roomSize: Pos = Pos(101, 103)): Int = {
30-
Iterator.from(0)
31-
.map(t => robots.map(_.step(t, roomSize))) // TODO: optimize
32-
.map(newRobots => newRobots.groupCount(_.pos))
33-
.indexWhere(_.values.forall(_ <= 1)) // look for arrangement with unique positions
32+
def findEasterEgg(robots: Seq[Robot], roomSize: Pos = inputRoomSize): (Seq[Robot], Int) = {
33+
Iterator.iterate(robots)(_.map(_.step(roomSize)))
34+
.zipWithIndex
35+
.find(_._1.groupCount(_.pos).values.forall(_ <= 1)) // look for arrangement with unique positions
36+
// TODO: optimize by stopping groupCount when some goes over 1
37+
.get
38+
}
39+
40+
def printRobots(robots: Seq[Robot], roomSize: Pos = inputRoomSize): Unit = {
41+
val posRobots = robots.groupCount(_.pos)
42+
43+
for (y <- 0 until roomSize.y) {
44+
for (x <- 0 until roomSize.x) {
45+
val pos = Pos(x, y)
46+
print(posRobots.get(pos).map(count => ('0' + count).toChar).getOrElse('.')) // TODO: toDigit?
47+
}
48+
println()
49+
}
3450
}
3551

3652
def parseRobot(s: String): Robot = s match {
@@ -44,6 +60,9 @@ object Day14 {
4460

4561
def main(args: Array[String]): Unit = {
4662
println(safetyFactor(parseRobots(input)))
47-
println(findEasterEgg(parseRobots(input)))
63+
64+
val (easterEggRobots, easterEggTime) = findEasterEgg(parseRobots(input))
65+
printRobots(easterEggRobots)
66+
println(easterEggTime)
4867
}
4968
}

‎src/test/scala/eu/sim642/adventofcode2024/Day14Test.scala‎

Lines changed: 113 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,8 @@ import Day14.*
44
import eu.sim642.adventofcodelib.pos.Pos
55
import org.scalatest.funsuite.AnyFunSuite
66

7+
import java.io.ByteArrayOutputStream
8+
79
class Day14Test extends AnyFunSuite {
810

911
val exampleInput =
@@ -29,6 +31,116 @@ class Day14Test extends AnyFunSuite {
2931
}
3032

3133
test("Part 2 input answer") {
32-
assert(findEasterEgg(parseRobots(input)) == 7093)
34+
val (easterEggRobots, easterEggTime) = findEasterEgg(parseRobots(input))
35+
assert(easterEggTime == 7093)
36+
37+
val out = new ByteArrayOutputStream()
38+
Console.withOut(out) {
39+
printRobots(easterEggRobots)
40+
}
41+
assert(out.toString.trim ==
42+
""".........................1...........................................................................
43+
|..............................1......................................................................
44+
|.....................................................................................1.........1.....
45+
|..............................................1.........................................1............
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|.....................................................................................................
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|.1.............1.....................................................................................
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|.....................................................................................................
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|......1.....1.......................................................1...................1............
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|1.........................................................................1..........................
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|..........................................1..........................................................
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|.....................................................................................................
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|..............................................................................1................1.....
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|................................1...1...............1..............................1.................
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|....................1................................................................................
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|.......................1........................................................1....................
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|...........1...........1.....................1.......................................................
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|...................................................1..........1......................................
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|..................1...........1...................................................................1..
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|.....................................................................................................
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|.................1...........................1.......................................................
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|................1..1................................1................................................
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|.....................................................................................................
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|.....................................................................................................
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|............................1.1.....1111111111111111111111111111111..................................
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|.1..................................1.............................1..................................
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|....................................1.............................1..................................
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|...1................................1.............................1..........................1.......
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|..........................1.........1.............................1...................1..............
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|....................................1..............1..............1..................................
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|...............................1....1.............111.............1..................................
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|....................................1............11111............1..................................
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|....................................1...........1111111...........1......................1........1..
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|....................................1..........111111111..........1............1................1....
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|....................................1............11111............1........1.........................
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|....................................1...........1111111...........1..................................
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|.....................1............1.1..........111111111..........1.1............................1...
78+
|....................................1.........11111111111.........1..................................
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|....................................1........1111111111111........1..................................
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|....................................1..........111111111..........1.1..................11............
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|....................................1.........11111111111.........1..................................
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|....................................1........1111111111111........1..................................
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|......................1.............1.......111111111111111.......1..................................
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|.......1............................1......11111111111111111......1..................................
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|...........1..1.....................1........1111111111111........1................1.................
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|....................................1.......111111111111111.......1...........................1......
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|....................................1......11111111111111111......1.....1.................1..........
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|......1.............................1.....1111111111111111111.....1..........1.......................
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|................1...................1....111111111111111111111....1...................1..............
90+
|..................................1.1.............111.............1..................................
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|....................................1.............111.............1......1...........................
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|....................................1.............111.............1..................................
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|....................................1.............................1..................................
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|............................1.......1.............................1..................................
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|....................................1.............................1..................................
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|...............1....................1.............................1..............1...................
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|..............1.........1...........1111111111111111111111111111111.....................1............
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|...........................1........................................1................................
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|....................1.....1................1..........................1..............................
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|............................1........................................................................
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|...............................................................................................1.....
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|.........................1......................................1....................................
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|.........................................................................1...1.......................
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|............................................1........................................................
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|.............................................................................1........1..............
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|.....................................................................................................
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|.....................................................................................................
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|...1............................................1..............1.....................................
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|.....................................................................................................
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|....................................................................................1............1...
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|..................................................................1..................................
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|................................1.......................1............................................
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|.....................................................................................................
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|......................1..............................................................................
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|..............................1............1.........................................................
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|..............................................................1......................................
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|................................................................1....................................
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|......................................1............................1....................1............
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|.....................................................................................................
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|.....................................................................................................
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|.........................................................................1....................1......
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|....................................1.......1............1.......1.........................1.........
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|.....................................................................................................
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|...................................1................................1................................
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|..........................................................................1..........................
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|.....................................................................1.........1.................1...
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|........................................1...........1...................1............................
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|.................................................................1....1..............................
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|...........................................1.........................................................
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|.....................................................................................................
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|.1....1............................................................................1.................
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|.........................................................1...........................................
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|..........................................................................................1..........
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|...................................1........................................................1........
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|........................1......................................1..........................1.1........
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|.......1..................................................................1.........................1
138+
|.....................................................................................................
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|.....................................................................................................
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|..................................................................1................................1.
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|.........................................................................1...........................
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|..........................1..........................................................................
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|.................................................................1...................................
144+
|...........1.........................................................................................""".stripMargin)
33145
}
34146
}

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