1 files changed, 31 insertions, 16 deletions
diff --git a/aoc2017-gleam/src/aoc_2017/day_12.gleam b/aoc2017-gleam/src/aoc_2017/day_12.gleam
index 87747d0..a9d73c5 100644
--- a/aoc2017-gleam/src/aoc_2017/day_12.gleam
+++ b/aoc2017-gleam/src/aoc_2017/day_12.gleam
@@ -1,29 +1,44 @@
-import gleam/dict.{type Dict}
-import gleam/int
+import gleam/dict
 import gleam/list
-import gleam/result
+import gleam/set.{type Set}
 import gleam/string
 
 type Pipes =
-  Dict(Int, List(Int))
+  dict.Dict(String, List(String))
 
 pub fn parse(input: String) -> Pipes {
-  {
-    use row <- list.map(string.split(input, "\n"))
-    let assert Ok(#(from, to)) = string.split_once(row, " <-> ")
-
-    let assert Ok(from) = int.parse(from)
-    let to = to |> string.split(", ") |> list.map(int.parse) |> result.values
-
-    #(from, to)
-  }
-  |> dict.from_list
+  use acc, row <- list.fold(string.split(input, "\n"), dict.new())
+  let assert Ok(#(from, to)) = string.split_once(row, " <-> ")
+  let to_nodes = string.split(to, ", ")
+  dict.insert(acc, from, to_nodes)
 }
 
 pub fn pt_1(input: Pipes) {
-  input
+  next_nodes("0", input, set.new()) |> set.size()
 }
 
 pub fn pt_2(input: Pipes) {
-  todo as "part 2 not implemented"
+  count_groups(dict.keys(input), input, 0)
+}
+
+fn next_nodes(current: String, pipes: Pipes, found: Set(String)) {
+  let assert Ok(to_nodes) = dict.get(pipes, current)
+
+  use acc, node <- list.fold(to_nodes, found)
+  case set.contains(found, node) {
+    False -> acc |> set.insert(node) |> next_nodes(node, pipes, _)
+    True -> acc
+  }
+}
+
+fn count_groups(all_nodes: List(String), pipes: Pipes, count: Int) {
+  case all_nodes {
+    [] -> count
+    [first, ..] -> {
+      let next_subgraph = next_nodes(first, pipes, set.new())
+      let remaining =
+        list.filter(all_nodes, fn(n) { !set.contains(next_subgraph, n) })
+      count_groups(remaining, pipes, count + 1)
+    }
+  }
 }