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Make Day 7 faster

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This commit is contained in:
Christian
2024-12-09 17:58:13 +01:00
parent eee695007d
commit 4c675c3ffe
1 changed files with 28 additions and 14 deletions
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42
aoc/src/dev/ctsk/aoc/days/Day07.scala
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@@ -8,33 +8,47 @@ object Day07 extends Solver(7):
while m * 10 <= b do m *= 10 while m * 10 <= b do m *= 10
a * (m * 10) + b a * (m * 10) + b
def deconcat(a: Long, b: Long): Option[Long] =
val b_len = Math.log10(b).floor.toLong + 1
if (a % Math.pow(10, b_len).toLong == b)
then Some(a / Math.pow(10, b_len).toLong)
else None
class Searcher(target: Long, nums: Vector[Long], elephants: Boolean): class Searcher(target: Long, nums: Vector[Long], elephants: Boolean):
def search(acc: Long = nums(0), pos: Int = 1): Boolean = def search(acc: Long = nums(0), pos: Int = 1): Boolean =
if (pos >= nums.length) return acc == target if (pos >= nums.length) return acc == target
if (acc > target) return false
search(acc + nums(pos), pos + 1) search(acc + nums(pos), pos + 1)
|| search(acc * nums(pos), pos + 1) || search(acc * nums(pos), pos + 1)
|| (elephants && search(concat(acc, nums(pos)), pos + 1)) || (elephants && search(concat(acc, nums(pos)), pos + 1))
class Tester(nums: Vector[Long], elephants: Boolean):
def test(target: Long, pos: Int = nums.length - 1): Boolean =
if pos == 0 then return target == nums(0)
if target <= 0 then return false
test(target - nums(pos), pos - 1)
|| (target % nums(pos) == 0 && test(target / nums(pos), pos - 1))
|| (elephants && deconcat(target, nums(pos)).exists(test(_, pos - 1)))
def check(target: Long, nums: Vector[Long], thirdElephant: Boolean): Boolean =
if nums.contains(0)
then Searcher(target, nums, thirdElephant).search()
else Tester(nums, thirdElephant).test(target)
def run(input: os.ReadablePath): (Timings, Solution) = def run(input: os.ReadablePath): (Timings, Solution) =
val REGEX = """(\d+): (.*)""".r val REGEX = """(\d+): (.*)""".r
val (pre_time, in) = timed { val (pre_time, in) = timed {
os.read.lines(input).map { os.read
case REGEX(value, rest) => (value.toLong, longs(rest)) .lines(input)
}.toVector .map { case REGEX(value, rest) => (value.toLong, longs(rest)) }
.toVector
} }
val (p1_time, p1_solution) = timed { val (p1_time, p1_solution) = timed {
in in.filter(p => check(p._1, p._2, false)).map(_.head).sum
.filter((target, nums) => Searcher(target, nums, false).search())
.map(_.head)
.sum
} }
val (p2_time, p2_solution) = timed { val (p2_time, p2_solution) = timed {
in in.filter(p => check(p._1, p._2, true)).map(_.head).sum
.filter((target, nums) => Searcher(target, nums, true).search())
.map(_.head)
.sum
} }
( (