Merge branch 'main' of https://github.com/hunkyjimpjorps/AdventOfCode

1 files changed, 85 insertions, 0 deletions

diff --git a/aoc2023-gleam/src/day6/solve.gleam b/aoc2023-gleam/src/day6/solve.gleam
new file mode 100644
index 0000000..88044c4
--- /dev/null
+++ b/aoc2023-gleam/src/day6/solve.gleam
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+import adglent.{First, Second}
+import gleam/io
+import gleam/string
+import gleam/int
+import gleam/list
+import gleam/result
+
+type Race {
+  Race(time: Int, distance: Int)
+}
+
+fn parse_with_bad_kerning(input: String) {
+  input
+  |> string.split("\n")
+  |> list.map(fn(str) {
+    str
+    |> string.split(" ")
+    |> list.map(int.parse)
+    |> result.values
+  })
+  |> list.transpose
+  |> list.map(fn(ns) {
+    let assert [t, d] = ns
+    Race(t, d)
+  })
+}
+
+fn find_bound(race: Race, button_time: Int, step: Int) {
+  let travel_time = race.time - button_time
+  case button_time * travel_time > race.distance {
+    True -> button_time
+    False -> find_bound(race, button_time + step, step)
+  }
+}
+
+fn lower_bound(race: Race) {
+  find_bound(race, 1, 1)
+}
+
+fn upper_bound(race: Race) {
+  find_bound(race, race.time, -1)
+}
+
+pub fn part1(input: String) {
+  {
+    use acc, race <- list.fold(parse_with_bad_kerning(input), 1)
+    acc * { upper_bound(race) - lower_bound(race) + 1 }
+  }
+  |> string.inspect
+}
+
+fn parse_properly(input: String) {
+  input
+  |> string.replace(" ", "")
+  |> string.split("\n")
+  |> list.flat_map(string.split(_, ":"))
+  |> list.map(int.parse)
+  |> result.values
+}
+
+pub fn part2(input: String) {
+  let assert [time, distance] =
+    input
+    |> parse_properly
+
+  let race = Race(time, distance)
+
+  upper_bound(race) - lower_bound(race) + 1
+  |> string.inspect
+}
+
+pub fn main() {
+  let assert Ok(part) = adglent.get_part()
+  let assert Ok(input) = adglent.get_input("6")
+  case part {
+    First ->
+      part1(input)
+      |> adglent.inspect
+      |> io.println
+    Second ->
+      part2(input)
+      |> adglent.inspect
+      |> io.println
+  }
+}