From ffaba850705af5a880038b611d9586573c2c5248 Mon Sep 17 00:00:00 2001
From: "J.J" <thechairman@thechairman.info>
Date: Sat, 23 Dec 2023 15:29:02 -0500
Subject: day 23 gleam cleanup

---
 aoc2023/src/day23/solve.gleam | 48 ++++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 28 deletions(-)

diff --git a/aoc2023/src/day23/solve.gleam b/aoc2023/src/day23/solve.gleam
index 916ef17..e1fe638 100644
--- a/aoc2023/src/day23/solve.gleam
+++ b/aoc2023/src/day23/solve.gleam
@@ -84,45 +84,37 @@ fn walk_to_next_junction(
   }
 }
 
+fn find_routes(junctions, trails) {
+  use junction <- list.flat_map(junctions)
+  use neighbor <- list.filter_map(junction_neighbors(junction))
+  case dict.has_key(trails, neighbor) {
+    True -> Ok(start_walking_to_next_junction(junction, neighbor, trails))
+    False -> Error(Nil)
+  }
+}
+
 fn generate_routes(
   junctions: List(Posn),
   trails: Array2D(Path),
 ) -> Dict(Posn, List(Route)) {
-  {
-    use junction <- list.flat_map(junctions)
-    use neighbor <- list.filter_map(junction_neighbors(junction))
-    case dict.has_key(trails, neighbor) {
-      True -> Ok(start_walking_to_next_junction(junction, neighbor, trails))
-      False -> Error(Nil)
-    }
-  }
-  |> list.fold(dict.new(), fn(acc, edge) {
-    let #(from, route) = edge
-    use v <- dict.update(acc, from)
-    case v {
-      None -> [route]
-      Some(routes) -> [route, ..routes]
-    }
-  })
+  use acc, #(from, route) <- list.fold(
+    find_routes(junctions, trails),
+    dict.new(),
+  )
+  dict.update(acc, from, append_to_key(_, route))
 }
 
 fn generate_2way_routes(
   junctions: List(Posn),
   trails: Array2D(Path),
 ) -> Dict(Posn, List(Route)) {
-  let routes = {
-    use junction <- list.flat_map(junctions)
-    use neighbor <- list.filter_map(junction_neighbors(junction))
-    case dict.has_key(trails, neighbor) {
-      True -> Ok(start_walking_to_next_junction(junction, neighbor, trails))
-      False -> Error(Nil)
-    }
-  }
-  use acc, r <- list.fold(routes, dict.new())
-  let #(from, Route(to, dist)) = r
+  use acc, #(from, route) <- list.fold(
+    find_routes(junctions, trails),
+    dict.new(),
+  )
   acc
-  |> dict.update(from, append_to_key(_, Route(to, dist)))
-  |> dict.update(to, append_to_key(_, Route(from, dist)))
+  |> dict.update(from, append_to_key(_, route))
+  |> dict.update(route.to, append_to_key(_, Route(from, route.distance)))
 }
 
 fn dfs(routes, from, to) {
-- 
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