gleam 2017 day 9

2 files changed, 49 insertions, 1 deletions

diff --git a/aoc2017-gleam/manifest.toml b/aoc2017-gleam/manifest.toml
index 12fa60f..e078678 100644
--- a/aoc2017-gleam/manifest.toml
+++ b/aoc2017-gleam/manifest.toml
@@ -27,7 +27,7 @@ packages = [
 ]
 
 [requirements]
-gary = { version = ">= 1.0.1 and < 2.0.0"}
+gary = { version = ">= 1.0.1 and < 2.0.0" }
 gladvent = { version = ">= 0.7.3 and < 1.0.0" }
 gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
 gleeunit = { version = ">= 1.0.0 and < 2.0.0" }
diff --git a/aoc2017-gleam/src/aoc_2017/day_9.gleam b/aoc2017-gleam/src/aoc_2017/day_9.gleam
new file mode 100644
index 0000000..90eb4b3
--- /dev/null
+++ b/aoc2017-gleam/src/aoc_2017/day_9.gleam
@@ -0,0 +1,48 @@
+import gleam/list
+import gleam/option.{Some}
+import gleam/regex
+import gleam/string
+
+pub fn parse(input: String) {
+  let assert Ok(cancel) = regex.from_string("!.")
+
+  replace(input, with: cancel)
+}
+
+pub fn pt_1(input: String) {
+  input
+  |> strip_to_brackets()
+  |> next_bracket(0, 1)
+}
+
+fn replace(input: String, with regex: regex.Regex) -> String {
+  input |> regex.split(with: regex) |> string.concat()
+}
+
+fn strip_to_brackets(input: String) -> String {
+  let assert Ok(garbage) = regex.from_string("<.*?>")
+  let assert Ok(not_group) = regex.from_string("[^{}]")
+
+  input
+  |> replace(with: garbage)
+  |> replace(with: not_group)
+}
+
+fn next_bracket(brackets: String, score: Int, depth: Int) -> Int {
+  case string.pop_grapheme(brackets) {
+    Error(Nil) -> score
+    Ok(#("{", rest)) -> next_bracket(rest, score + depth, depth + 1)
+    Ok(#("}", rest)) -> next_bracket(rest, score, depth - 1)
+    _ -> panic as "unrecognized character"
+  }
+}
+
+pub fn pt_2(input: String) {
+  let assert Ok(garbage) = regex.from_string("<(.*?)>")
+
+  use acc, match <- list.fold(regex.scan(input, with: garbage), 0)
+  case match.submatches {
+    [Some(g)] -> string.length(g) + acc
+    _ -> acc
+  }
+}