day 8 complete

5 files changed, 158 insertions, 4 deletions

diff --git a/aoc2023/gleam.toml b/aoc2023/gleam.toml
index 387036d..8fc812a 100644
--- a/aoc2023/gleam.toml
+++ b/aoc2023/gleam.toml
@@ -14,6 +14,7 @@ gleam = ">= 0.32.0"
 gleam_stdlib = "~> 0.32"
 simplifile = "~> 1.0"
 gleam_erlang = "~> 0.23"
+gleam_community_maths = "~> 1.0"
 
 [dev-dependencies]
 gleeunit = "~> 1.0"
diff --git a/aoc2023/manifest.toml b/aoc2023/manifest.toml
index aea86fb..b6965da 100644
--- a/aoc2023/manifest.toml
+++ b/aoc2023/manifest.toml
@@ -2,17 +2,18 @@
 # You typically do not need to edit this file
 
 packages = [
-  { name = "adglent", version = "1.2.0", build_tools = ["gleam"], requirements = ["tom", "gleam_http", "gleam_stdlib", "simplifile", "gleam_community_ansi", "gap", "gleam_httpc", "gleam_otp", "snag", "glint", "gleam_erlang"], otp_app = "adglent", source = "hex", outer_checksum = "A20D35001061F8AD602E3B92FB3AC0E1E4EEC642AD2AAE0ACEAD3A85F37DA7F0" },
+  { name = "adglent", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_otp", "gap", "glint", "gleam_http", "snag", "gleam_stdlib", "tom", "gleam_community_ansi", "gleam_erlang", "gleam_httpc", "simplifile"], otp_app = "adglent", source = "hex", outer_checksum = "A20D35001061F8AD602E3B92FB3AC0E1E4EEC642AD2AAE0ACEAD3A85F37DA7F0" },
   { name = "gap", version = "1.0.1", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_community_ansi"], otp_app = "gap", source = "hex", outer_checksum = "5E369751DB547BFBDA7735878DC04DA31FCA3112193D61D5D7566010C7C8BA98" },
-  { name = "gleam_community_ansi", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_community_colour", "gleam_stdlib"], otp_app = "gleam_community_ansi", source = "hex", outer_checksum = "8B5A9677BC5A2738712BBAF2BA289B1D8195FDF962BBC769569976AD5E9794E1" },
+  { name = "gleam_community_ansi", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_community_colour"], otp_app = "gleam_community_ansi", source = "hex", outer_checksum = "8B5A9677BC5A2738712BBAF2BA289B1D8195FDF962BBC769569976AD5E9794E1" },
   { name = "gleam_community_colour", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "036C206886AFB9F153C552700A7A0B4D2864E3BC96A20C77E5F34A013C051BE3" },
+  { name = "gleam_community_maths", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_community_maths", source = "hex", outer_checksum = "2F85C076830150347FBA286C3C440EC2CFB3538407105E5EF3FC64D17E711AC2" },
   { name = "gleam_erlang", version = "0.23.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "C21CFB816C114784E669FFF4BBF433535EEA9960FA2F216209B8691E87156B96" },
   { name = "gleam_http", version = "3.5.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_http", source = "hex", outer_checksum = "AECDA43AFD523D07A8F09068598A6E271C505278A0CB6F9C7A2E4365EAE8D11E" },
-  { name = "gleam_httpc", version = "2.1.1", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_http"], otp_app = "gleam_httpc", source = "hex", outer_checksum = "06AC1CA52C9BAA66C9D5C0303B2BF34E39AA1546BB96AEE496E4B06D513AB8C7" },
+  { name = "gleam_httpc", version = "2.1.1", build_tools = ["gleam"], requirements = ["gleam_http", "gleam_stdlib"], otp_app = "gleam_httpc", source = "hex", outer_checksum = "06AC1CA52C9BAA66C9D5C0303B2BF34E39AA1546BB96AEE496E4B06D513AB8C7" },
   { name = "gleam_otp", version = "0.8.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "18EF8242A5E54BA92F717C7222F03B3228AEE00D1F286D4C56C3E8C18AA2588E" },
   { name = "gleam_stdlib", version = "0.33.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "539E37A2AA5EBE8E75F4B74755E4CC604BD957C3000AC8D705A2024886A2738B" },
   { name = "gleeunit", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "D3682ED8C5F9CAE1C928F2506DE91625588CC752495988CBE0F5653A42A6F334" },
-  { name = "glint", version = "0.13.0", build_tools = ["gleam"], requirements = ["gleam_community_ansi", "gleam_stdlib", "gleam_community_colour", "snag"], otp_app = "glint", source = "hex", outer_checksum = "46E56049CD370D61F720D319D0AB970408C9336EEB918F08B5DCB1DCE9845FA3" },
+  { name = "glint", version = "0.13.0", build_tools = ["gleam"], requirements = ["gleam_community_colour", "gleam_stdlib", "gleam_community_ansi", "snag"], otp_app = "glint", source = "hex", outer_checksum = "46E56049CD370D61F720D319D0AB970408C9336EEB918F08B5DCB1DCE9845FA3" },
   { name = "simplifile", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "0BD6F0E7DA1A7E11D18B8AD48453225CAFCA4C8CFB4513D217B372D2866C501C" },
   { name = "snag", version = "0.2.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "snag", source = "hex", outer_checksum = "8FD70D8FB3728E08AC425283BB509BB0F012BE1AE218424A597CDE001B0EE589" },
   { name = "tom", version = "0.2.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "tom", source = "hex", outer_checksum = "5C5A9B8586C547F1F39542B1A3BBD9FEE17AFEAB51CE53B32B13D0D46B421249" },
@@ -20,6 +21,7 @@ packages = [
 
 [requirements]
 adglent = { version = "~> 1.2" }
+gleam_community_maths = { version = "~> 1.0" }
 gleam_erlang = { version = "~> 0.23" }
 gleam_stdlib = { version = "~> 0.32" }
 gleeunit = { version = "~> 1.0" }
diff --git a/aoc2023/src/day8/.gitignore b/aoc2023/src/day8/.gitignore
new file mode 100644
index 0000000..ae40cea
--- /dev/null
+++ b/aoc2023/src/day8/.gitignore
@@ -0,0 +1 @@
+input.txt
\ No newline at end of file
diff --git a/aoc2023/src/day8/solve.gleam b/aoc2023/src/day8/solve.gleam
new file mode 100644
index 0000000..dee24a4
--- /dev/null
+++ b/aoc2023/src/day8/solve.gleam
@@ -0,0 +1,89 @@
+import adglent.{First, Second}
+import gleam/bool
+import gleam/dict.{type Dict}
+import gleam/io
+import gleam/iterator.{Next}
+import gleam/list
+import gleam/option.{Some}
+import gleam/string
+import gleam/regex.{type Match, Match}
+import gleam_community/maths/arithmetics
+
+type Paths {
+  Paths(to_left: String, to_right: String)
+}
+
+type Maze =
+  Dict(String, Paths)
+
+fn parse(input: String) {
+  let [directions_str, maze_str] = string.split(input, "\n\n")
+
+  let directions =
+    directions_str
+    |> string.to_graphemes()
+    |> iterator.from_list
+    |> iterator.cycle
+
+  let assert Ok(re) = regex.from_string("(...) = \\((...), (...)\\)")
+  let maze =
+    maze_str
+    |> string.split("\n")
+    |> list.map(fn(str) {
+      let assert [Match(submatches: [Some(name), Some(left), Some(right)], ..)] =
+        regex.scan(re, str)
+      #(name, Paths(left, right))
+    })
+    |> dict.from_list
+
+  #(directions, maze)
+}
+
+fn to_next_step(current, stop_at, count, directions, maze: Maze) {
+  use <- bool.guard(string.ends_with(current, stop_at), count)
+  let assert Next(next_direction, rest_directions) = iterator.step(directions)
+  let assert Ok(paths) = dict.get(maze, current)
+  case next_direction {
+    "L" -> paths.to_left
+    "R" -> paths.to_right
+  }
+  |> to_next_step(stop_at, count + 1, rest_directions, maze)
+}
+
+pub fn part1(input: String) {
+  let #(directions, maze) = parse(input)
+
+  to_next_step("AAA", "ZZZ", 0, directions, maze)
+  |> string.inspect
+}
+
+pub fn part2(input: String) {
+  let #(directions, maze) = parse(input)
+
+  maze
+  |> dict.keys
+  |> list.filter(string.ends_with(_, "A"))
+  |> list.fold(
+    1,
+    fn(acc, name) {
+      to_next_step(name, "Z", 0, directions, maze)
+      |> arithmetics.lcm(acc)
+    },
+  )
+  |> string.inspect
+}
+
+pub fn main() {
+  let assert Ok(part) = adglent.get_part()
+  let assert Ok(input) = adglent.get_input("8")
+  case part {
+    First ->
+      part1(input)
+      |> adglent.inspect
+      |> io.println
+    Second ->
+      part2(input)
+      |> adglent.inspect
+      |> io.println
+  }
+}
diff --git a/aoc2023/test/day8/day8_test.gleam b/aoc2023/test/day8/day8_test.gleam
new file mode 100644
index 0000000..e54d887
--- /dev/null
+++ b/aoc2023/test/day8/day8_test.gleam
@@ -0,0 +1,61 @@
+import gleam/list
+import showtime/tests/should
+import adglent.{type Example, Example}
+import day8/solve
+
+type Problem1AnswerType =
+  String
+
+type Problem2AnswerType =
+  String
+
+/// Add examples for part 1 here:
+/// ```gleam
+///const part1_examples: List(Example(Problem1AnswerType)) = [Example("some input", "")]
+/// ```
+const part1_examples: List(Example(Problem1AnswerType)) = [
+  Example(
+    "LLR
+
+AAA = (BBB, BBB)
+BBB = (AAA, ZZZ)
+ZZZ = (ZZZ, ZZZ)",
+    "6",
+  ),
+]
+
+/// Add examples for part 2 here:
+/// ```gleam
+///const part2_examples: List(Example(Problem2AnswerType)) = [Example("some input", "")]
+/// ```
+const part2_examples: List(Example(Problem2AnswerType)) = [
+  Example(
+    "LR
+
+11A = (11B, XXX)
+11B = (XXX, 11Z)
+11Z = (11B, XXX)
+22A = (22B, XXX)
+22B = (22C, 22C)
+22C = (22Z, 22Z)
+22Z = (22B, 22B)
+XXX = (XXX, XXX)",
+    "6",
+  ),
+]
+
+pub fn part1_test() {
+  part1_examples
+  |> should.not_equal([])
+  use example <- list.map(part1_examples)
+  solve.part1(example.input)
+  |> should.equal(example.answer)
+}
+
+pub fn part2_test() {
+  part2_examples
+  |> should.not_equal([])
+  use example <- list.map(part2_examples)
+  solve.part2(example.input)
+  |> should.equal(example.answer)
+}