Solution for Day 1 part 2

gleam.toml

@@ -15,6 +15,7 @@ version = "1.0.0"
 [dependencies]
 gleam_stdlib = ">= 0.34.0 and < 2.0.0"
 simplifile = ">= 2.2.0 and < 3.0.0"
+party = ">= 1.0.5 and < 2.0.0"
 
 [dev-dependencies]
 glacier = ">= 1.1.0 and < 2.0.0"

manifest.toml

@@ -11,11 +11,13 @@ packages = [
   { name = "gleam_community_colour", version = "1.4.1", build_tools = ["gleam"], requirements = ["gleam_json", "gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "386CB9B01B33371538672EEA8A6375A0A0ADEF41F17C86DDCB81C92AD00DA610" },
   { name = "gleam_json", version = "2.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "0A57FB5666E695FD2BEE74C0428A98B0FC11A395D2C7B4CDF5E22C5DD32C74C6" },
   { name = "gleam_stdlib", version = "0.45.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "206FCE1A76974AECFC55AEBCD0217D59EDE4E408C016E2CFCCC8FF51278F186E" },
+  { name = "party", version = "1.0.5", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "party", source = "hex", outer_checksum = "99456722503230EA6498B2F618C3A227269430427669A11B24C4F6655CA4CD31" },
   { name = "shellout", version = "1.6.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "shellout", source = "hex", outer_checksum = "E2FCD18957F0E9F67E1F497FC9FF57393392F8A9BAEAEA4779541DE7A68DD7E0" },
   { name = "simplifile", version = "2.2.0", build_tools = ["gleam"], requirements = ["filepath", "gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "0DFABEF7DC7A9E2FF4BB27B108034E60C81BEBFCB7AB816B9E7E18ED4503ACD8" },
 ]
 
 [requirements]
 glacier = { version = ">= 1.1.0 and < 2.0.0" }
 gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
+party = { version = ">= 1.0.5 and < 2.0.0" }
 simplifile = { version = ">= 2.2.0 and < 3.0.0" }

src/day01/part2.gleam

@@ -0,0 +1,38 @@
+import gleam/int
+import gleam/io
+import gleam/list
+import gleam/string
+import party.{do, return}
+import simplifile
+
+pub fn main() {
+  let assert Ok(content) = simplifile.read("inputs/day01.txt")
+  content
+  |> parse
+  |> process
+  |> int.to_string
+  |> io.println
+}
+
+pub fn parse(content) {
+  let assert Ok(rows) = string.trim(content) |> party.go(parser(), _)
+  rows
+}
+
+fn parser() {
+  let line_parser = {
+    use left <- do(party.digits() |> party.try(int.parse))
+    use _ <- do(party.whitespace())
+    use right <- do(party.digits() |> party.try(int.parse))
+    return([left, right])
+  }
+  party.sep(line_parser, by: party.string("\n"))
+}
+
+pub fn process(rows) {
+  let assert [lefts, rights] = list.transpose(rows)
+  list.fold(lefts, 0, fn(acc, left) {
+    let count = list.count(rights, where: fn(right) { right == left })
+    acc + left * count
+  })
+}

test/day01/part2_test.gleam

@@ -0,0 +1,12 @@
+import day01/part2 as solution
+import glacier/should
+
+pub fn parse_test() {
+  solution.parse("1   2\n3   4\n")
+  |> should.equal([[1, 2], [3, 4]])
+}
+
+pub fn process_test() {
+  solution.process([[3, 3], [5, 3], [2, 5]])
+  |> should.equal(3 * 2 + 5)
+}