Solve part 1 of day 20

2 files changed, 30 insertions, 0 deletions

diff --git a/aoc-2020-gleam/src/util/grid.gleam b/aoc-2020-gleam/src/util/grid.gleam
new file mode 100644
index 0000000..a091be5
--- /dev/null
+++ b/aoc-2020-gleam/src/util/grid.gleam
@@ -0,0 +1,22 @@
+import gleam/list
+import gleam/string as str
+import gleam/set.{type Set}
+
+pub fn parse_grid(lines: String, with constructor: fn(Int, Int) -> a) -> Set(a) {
+  lines
+  |> str.split("\n")
+  |> list.index_map(with: fn(line, y) {
+    line
+    |> str.to_graphemes
+    |> list.index_map(with: fn(grapheme, x) {
+      case grapheme {
+        "#" -> [constructor(x, y)]
+        "." -> []
+        _ -> panic
+      }
+    })
+    |> list.flatten
+  })
+  |> list.flatten
+  |> set.from_list
+}
diff --git a/aoc-2020-gleam/src/util/pos2.gleam b/aoc-2020-gleam/src/util/pos2.gleam
index 0b6256c..3f478ac 100644
--- a/aoc-2020-gleam/src/util/pos2.gleam
+++ b/aoc-2020-gleam/src/util/pos2.gleam
@@ -8,6 +8,14 @@ pub type Pos2 =
 
 pub const zero = #(0, 0)
 
+pub fn x(pos: Pos2) -> Int {
+  pos.0
+}
+
+pub fn y(pos: Pos2) -> Int {
+  pos.1
+}
+
 pub fn directions8() -> Set(Pos2) {
   set.from_list({
     use x <- list.flat_map(over: [-1, 0, 1])