1 files changed, 51 insertions, 0 deletions
diff --git a/aoc-2020-gleam/src/days/day24.gleam b/aoc-2020-gleam/src/days/day24.gleam
new file mode 100644
index 0000000..66bedb8
--- /dev/null
+++ b/aoc-2020-gleam/src/days/day24.gleam
@@ -0,0 +1,51 @@
+import gleam/io
+import gleam/set
+import gleam/list
+import ext/setx
+import ext/resultx as resx
+import util/input_util
+import util/parser as p
+import util/hex.{type Hex}
+
+fn parse_tiles(lines: List(String)) -> List(Hex) {
+  let tile_parser =
+    [
+      p.replace(p.literal("e"), with: hex.e),
+      p.replace(p.literal("se"), with: hex.se),
+      p.replace(p.literal("sw"), with: hex.sw),
+      p.replace(p.literal("w"), with: hex.w),
+      p.replace(p.literal("nw"), with: hex.nw),
+      p.replace(p.literal("ne"), with: hex.ne),
+    ]
+    |> p.any
+    |> p.many1
+    |> p.map(with: list.fold(over: _, from: hex.zero, with: hex.add))
+
+  list.map(lines, with: fn(line) {
+    line
+    |> p.parse_entire(with: tile_parser)
+    |> resx.assert_unwrap
+  })
+}
+
+fn part1(lines: List(String)) -> Int {
+  let tiles = parse_tiles(lines)
+  let blacks = list.fold(over: tiles, from: set.new(), with: setx.toggle)
+  set.size(blacks)
+}
+
+fn part2(lines: List(String)) -> Nil {
+  Nil
+}
+
+pub fn main() -> Nil {
+  let testing = input_util.read_lines("test24")
+  let assert 10 = part1(testing)
+  io.debug(part2(testing))
+
+  let input = input_util.read_lines("day24")
+  io.debug(part1(input))
+  io.debug(part2(input))
+
+  Nil
+}