Day 1 part 1

Author: timocp

gleam.toml

@@ -14,6 +14,8 @@ version = "1.0.0"
 
 [dependencies]
 gleam_stdlib = ">= 0.34.0 and < 2.0.0"
+argv = ">= 1.0.2 and < 2.0.0"
+simplifile = ">= 2.2.0 and < 3.0.0"
 
 [dev-dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

@@ -2,10 +2,15 @@
 # You typically do not need to edit this file
 
 packages = [
+  { name = "argv", version = "1.0.2", build_tools = ["gleam"], requirements = [], otp_app = "argv", source = "hex", outer_checksum = "BA1FF0929525DEBA1CE67256E5ADF77A7CDDFE729E3E3F57A5BDCAA031DED09D" },
+  { name = "filepath", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "67A6D15FB39EEB69DD31F8C145BB5A421790581BD6AA14B33D64D5A55DBD6587" },
   { name = "gleam_stdlib", version = "0.51.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "14AFA8D3DDD7045203D422715DBB822D1725992A31DF35A08D97389014B74B68" },
   { name = "gleeunit", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "F7A7228925D3EE7D0813C922E062BFD6D7E9310F0BEE585D3A42F3307E3CFD13" },
+  { name = "simplifile", version = "2.2.0", build_tools = ["gleam"], requirements = ["filepath", "gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "0DFABEF7DC7A9E2FF4BB27B108034E60C81BEBFCB7AB816B9E7E18ED4503ACD8" },
 ]
 
 [requirements]
+argv = { version = ">= 1.0.2 and < 2.0.0" }
 gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
 gleeunit = { version = ">= 1.0.0 and < 2.0.0" }
+simplifile = { version = ">= 2.2.0 and < 3.0.0" }

src/adventofcode2024.gleam

@@ -1,5 +1,25 @@
+import gleam/int
 import gleam/io
 
+import simplifile
+
+import day1
+
 pub fn main() {
-  io.println("Hello from adventofcode2024!")
+  run(1)
+}
+
+fn run(n: Int) -> Nil {
+  let input = read_input(n)
+  io.print("Day " <> int.to_string(n) <> " Part 1: ")
+  io.println(int.to_string(day1.part1(input)))
+}
+
+fn read_input(n: Int) -> String {
+  let filename = "input/day" <> int.to_string(n) <> ".txt"
+  case simplifile.read(from: filename) {
+    Ok(data) -> data
+    Error(_data) ->
+      panic as { "Input data missing for day " <> int.to_string(n) }
+  }
 }

src/day1.gleam

@@ -0,0 +1,23 @@
+import gleam/int
+import gleam/list
+import gleam/string
+
+pub fn part1(input: String) -> Int {
+  let #(left, right) = parse_input(input)
+  list.zip(left, right)
+  |> list.fold(0, fn(acc, pair) { acc + int.absolute_value(pair.0 - pair.1) })
+}
+
+fn parse_input(input: String) -> #(List(Int), List(Int)) {
+  let data =
+    input
+    |> string.split("\n")
+    |> list.filter(fn(line) { line != "" })
+    |> list.map(fn(line) {
+      line |> string.split(" ") |> list.filter_map(fn(str) { int.parse(str) })
+    })
+  #(
+    data |> list.filter_map(list.first) |> list.sort(by: int.compare),
+    data |> list.filter_map(list.last) |> list.sort(by: int.compare),
+  )
+}

test/day1_test.gleam

@@ -0,0 +1,20 @@
+import gleeunit
+import gleeunit/should
+
+import day1
+
+pub fn main() {
+  gleeunit.main()
+}
+
+const example1 = "3   4
+4   3
+2   5
+1   3
+3   9
+3   3
+"
+
+pub fn part1_test() {
+  day1.part1(example1) |> should.equal(11)
+}