1 files changed, 32 insertions, 0 deletions
diff --git a/gleam/aoc2017/src/aoc_2017/day_1.gleam b/gleam/aoc2017/src/aoc_2017/day_1.gleam
new file mode 100644
index 0000000..786d0dd
--- /dev/null
+++ b/gleam/aoc2017/src/aoc_2017/day_1.gleam
@@ -0,0 +1,32 @@
+import gleam/int
+import gleam/list
+import gleam/result
+import gleam/string
+
+pub fn parse(input: String) {
+  input
+  |> string.to_graphemes()
+  |> list.map(int.parse)
+  |> result.values()
+}
+
+pub fn pt_1(input: List(Int)) {
+  pair_by(numbers: input, considering: 1)
+}
+
+pub fn pt_2(input: List(Int)) {
+  pair_by(numbers: input, considering: list.length(input) / 2)
+}
+
+fn find_neighbor_matches(number_pairs: List(#(Int, Int))) {
+  case number_pairs {
+    [] -> 0
+    [#(a, b), ..rest] if a == b -> a + find_neighbor_matches(rest)
+    [_, ..rest] -> find_neighbor_matches(rest)
+  }
+}
+
+fn pair_by(numbers xs: List(Int), considering by: Int) {
+  list.zip(xs, list.append(list.drop(xs, by), list.take(xs, by)))
+  |> find_neighbor_matches()
+}