Day 3 Dusted

2024/gleam.toml

@@ -18,6 +18,7 @@ file_streams = ">= 1.2.2 and < 2.0.0"
 simplifile = ">= 2.2.0 and < 3.0.0"
 gleave = ">= 1.0.0 and < 2.0.0"
 filepath = ">= 1.1.0 and < 2.0.0"
+gleam_regexp = ">= 1.0.0 and < 2.0.0"
 
 [dev-dependencies]
 gleeunit = ">= 1.0.0 and < 2.0.0"

2024/manifest.toml

@@ -4,6 +4,7 @@
 packages = [
   { name = "file_streams", version = "1.2.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "file_streams", source = "hex", outer_checksum = "E8659E84092A720CB8D737FE6E529B9B7597E92B4B2A70A917E8590FBEAD0AE6" },
   { name = "filepath", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "67A6D15FB39EEB69DD31F8C145BB5A421790581BD6AA14B33D64D5A55DBD6587" },
+  { name = "gleam_regexp", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_regexp", source = "hex", outer_checksum = "A3655FDD288571E90EE9C4009B719FEF59FA16AFCDF3952A76A125AF23CF1592" },
   { name = "gleam_stdlib", version = "0.45.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "206FCE1A76974AECFC55AEBCD0217D59EDE4E408C016E2CFCCC8FF51278F186E" },
   { name = "gleave", version = "1.0.0", build_tools = ["gleam"], requirements = [], otp_app = "gleave", source = "hex", outer_checksum = "EBEB0DF9C764A6CB22623FF6F03A0BC978D75225303F3BBDEEB705A2DD700D0D" },
   { name = "gleeunit", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "F7A7228925D3EE7D0813C922E062BFD6D7E9310F0BEE585D3A42F3307E3CFD13" },
@@ -13,6 +14,7 @@ packages = [
 [requirements]
 file_streams = { version = ">= 1.2.2 and < 2.0.0" }
 filepath = { version = ">= 1.1.0 and < 2.0.0" }
+gleam_regexp = { version = ">= 1.0.0 and < 2.0.0" }
 gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
 gleave = { version = ">= 1.0.0 and < 2.0.0" }
 gleeunit = { version = ">= 1.0.0 and < 2.0.0" }

2024/src/day3.gleam

@@ -0,0 +1,100 @@
+import gleam/int
+import gleam/io
+import gleam/list
+import gleam/option.{None, Some}
+import gleam/regexp
+import gleam/string
+import utils.{read_file}
+
+pub fn main() {
+  let input = case read_file("day3.input") {
+    Ok(s) -> s
+    _ -> "dunno"
+  }
+
+  io.debug(part1(input))
+  io.debug(part2(input))
+}
+
+fn process(list: List(String), signal: Bool, acc: List(Int)) -> List(Int) {
+  case list {
+    [] -> acc
+    [head, ..rest] -> {
+      case int.parse(head) {
+        Ok(v) -> {
+          let new_acc = case signal {
+            True -> {
+              list.append(acc, [v])
+            }
+            False -> {
+              acc
+            }
+          }
+          process(rest, signal, new_acc)
+        }
+        Error(_) -> {
+          case head {
+            "do" -> process(rest, True, acc)
+            "don't" -> process(rest, False, acc)
+            _ -> process(rest, signal, acc)
+          }
+        }
+      }
+    }
+  }
+}
+
+fn filter_mem(l: List(String)) -> List(Int) {
+  process(l, True, [])
+}
+
+fn mult_pairs(l: List(Int)) -> List(Int) {
+  case l {
+    [a, b, ..rest] -> {
+      list.append([a * b], mult_pairs(rest))
+    }
+    _ -> [0]
+  }
+}
+
+pub fn part1(input: String) -> Int {
+  let assert Ok(re) = regexp.from_string("mul\\((\\d+),(\\d+)\\)")
+
+  input
+  |> string.split("\n")
+  |> list.map(fn(line: String) {
+    regexp.scan(re, line)
+    |> list.flat_map(fn(match: regexp.Match) { match.submatches })
+  })
+  |> list.flat_map(fn(sml) {
+    list.map(sml, fn(sm) {
+      case sm {
+        Some(s) -> {
+          case int.parse(s) {
+            Ok(v) -> v
+            Error(_) -> 1
+          }
+        }
+        None -> 1
+      }
+    })
+  })
+  // |> io.debug
+  |> mult_pairs()
+  |> int.sum()
+}
+
+pub fn part2(input: String) -> Int {
+  let assert Ok(re) = regexp.from_string("mul\\((\\d+),(\\d+)\\)|(do(?:n't)?)*")
+
+  input
+  |> string.split("\n")
+  |> list.flat_map(fn(line: String) {
+    regexp.scan(re, line)
+    |> list.flat_map(fn(match: regexp.Match) { match.submatches })
+  })
+  |> option.values
+  |> filter_mem()
+  |> mult_pairs()
+  |> int.sum()
+}