day01

2024/.gitignore

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+input*.txt
+mise.toml

2024/day01/.gitignore

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+*.beam
+*.ez
+/build
+erl_crash.dump

2024/day01/gleam.toml

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+name = "day01"
+version = "1.0.0"
+
+# Fill out these fields if you intend to generate HTML documentation or publish
+# your project to the Hex package manager.
+#
+# description = ""
+# licences = ["Apache-2.0"]
+# repository = { type = "github", user = "", repo = "" }
+# links = [{ title = "Website", href = "" }]
+#
+# For a full reference of all the available options, you can have a look at
+# https://gleam.run/writing-gleam/gleam-toml/.
+
+[dependencies]
+gleam_stdlib = ">= 0.34.0 and < 2.0.0"
+gleam_yielder = ">= 1.1.0 and < 2.0.0"
+
+[dev-dependencies]
+gleeunit = ">= 1.0.0 and < 2.0.0"

2024/day01/manifest.toml

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+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "gleam_stdlib", version = "0.45.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "206FCE1A76974AECFC55AEBCD0217D59EDE4E408C016E2CFCCC8FF51278F186E" },
+  { name = "gleam_yielder", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_yielder", source = "hex", outer_checksum = "8E4E4ECFA7982859F430C57F549200C7749823C106759F4A19A78AEA6687717A" },
+  { name = "gleeunit", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "F7A7228925D3EE7D0813C922E062BFD6D7E9310F0BEE585D3A42F3307E3CFD13" },
+]
+
+[requirements]
+gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
+gleam_yielder = { version = ">= 1.1.0 and < 2.0.0" }
+gleeunit = { version = ">= 1.0.0 and < 2.0.0" }

2024/day01/src/day01.gleam

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+import gleam/dict
+import gleam/int
+import gleam/io
+import gleam/list
+import gleam/pair
+import gleam/result
+import gleam/string
+import gleam/yielder
+import stdin.{stdin}
+
+pub fn main() {
+  let assert #(pairs, []) =
+    stdin()
+    |> yielder.map(fn(l) {
+      string.trim_end(l)
+      |> string.split_once("   ")
+      |> result.map(fn(p) {
+        p |> pair.map_first(int.parse) |> pair.map_second(int.parse)
+      })
+    })
+    |> yielder.to_list
+    |> result.partition
+  let #(a, b) = list.unzip(pairs)
+  let assert #(a, []) = result.partition(a)
+  let assert #(b, []) = result.partition(b)
+
+  part1(a, b)
+  |> int.to_string
+  |> io.println
+
+  part2(a, b)
+  |> int.to_string
+  |> io.println
+}
+
+fn part1(a: List(Int), b: List(Int)) -> Int {
+  list.zip(list.sort(a, int.compare), list.sort(b, int.compare))
+  |> list.map(fn(p) { p.0 - p.1 |> int.absolute_value })
+  |> int.sum
+}
+
+fn part2(a: List(Int), b: List(Int)) -> Int {
+  let count =
+    list.unique(b)
+    |> list.fold(dict.new(), fn(d, i) {
+      dict.insert(d, i, list.count(b, fn(x) { x == i }))
+    })
+  list.fold(a, 0, fn(s, x) {
+    s + x * { dict.get(count, x) |> result.unwrap(0) }
+  })
+}

2024/day01/src/stdin.gleam

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+import gleam/dynamic
+import gleam/result
+import gleam/yielder
+
+@external(erlang, "io", "get_line")
+fn ffi_read_line(prompt: String) -> dynamic.Dynamic
+
+fn read_line() -> Result(String, Nil) {
+  ffi_read_line("")
+  |> dynamic.from()
+  |> dynamic.string()
+  |> result.replace_error(Nil)
+}
+
+fn assert_upwrap(res: Result(a, _)) -> a {
+  let assert Ok(a) = res
+  a
+}
+
+pub fn stdin() -> yielder.Yielder(String) {
+  yielder.repeatedly(read_line)
+  |> yielder.take_while(result.is_ok)
+  |> yielder.map(assert_upwrap)
+}