Add solution for "Day 1: Secret Entrance", part 1

Cargo.lock

@@ -7,7 +7,18 @@ name = "advent_of_code_2025"
 version = "0.1.0"
 dependencies = [
  "grid",
+ "regex",
  "sanitise-file-name",
+ "scan_fmt",
+]
+
+[[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
 ]
 
 [[package]]
@@ -16,8 +27,52 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f9e2d4c0a8296178d8802098410ca05d86b17a10bb5ab559b3fb404c1f948220"
 
+[[package]]
+name = "memchr"
+version = "2.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f52b00d39961fc5b2736ea853c9cc86238e165017a493d1d5c8eac6bdc4cc273"
+
+[[package]]
+name = "regex"
+version = "1.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5276caf25ac86c8d810222b3dbb938e512c55c6831a10f3e6ed1c93b84041f1c"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
+
 [[package]]
 name = "sanitise-file-name"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19d36299972b96b8ae7e8f04ecbf75fb41a27bf3781af00abcf57609774cb911"
+
+[[package]]
+name = "scan_fmt"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b53b0a5db882a8e2fdaae0a43f7b39e7e9082389e978398bdf223a55b581248"
+dependencies = [
+ "regex",
+]

Cargo.toml

@@ -5,4 +5,6 @@ edition = "2024"
 
 [dependencies]
 grid = "1.0.0"
+regex = "1.12.2"
 sanitise-file-name = "1.0.0"
+scan_fmt = "0.2.6"

src/lib.rs

@@ -1,2 +1,5 @@
+#[macro_use]
+extern crate scan_fmt;
+
 mod common;
 pub mod solvers;

src/main.rs

@@ -2,7 +2,7 @@ use advent_of_code_2025::solvers;
 
 fn main() {
     println!("### Advent of Code 2025 ###\n");
-    // SecretEntrance
+    solvers::run(solvers::secret_entrance::SecretEntrance {});
     // GiftShop
     // Lobby
     solvers::run(solvers::printing_department::PrintingDepartment {});
@@ -11,4 +11,7 @@ fn main() {
     // Laboratories
     solvers::run(solvers::playground::Playground::new(None));
     solvers::run(solvers::movie_theater::MovieTheater {});
+    // Factory
+    // Reactor
+    // ChristmasTreeFarm
 }

src/solvers.rs

@@ -9,6 +9,7 @@ pub mod cafeteria;
 pub mod movie_theater;
 pub mod playground;
 pub mod printing_department;
+pub mod secret_entrance;
 pub mod trash_compactor;
 
 pub trait Solver {

src/solvers/secret_entrance.rs

@@ -0,0 +1,42 @@
+use crate::solvers::Solver;
+use std::io::BufRead;
+
+pub struct SecretEntrance {}
+
+impl SecretEntrance {
+    const START_POSITION: i32 = 50;
+    const DIAL_SIZE: i32 = 100;
+    const COUNT_POSITION: i32 = 0;
+    const POSITIVE_SIGN_CHAR: char = 'R';
+    const NEGATIVE_SIGN_CHAR: char = 'L';
+}
+
+impl Solver for SecretEntrance {
+    const PUZZLE_INDEX: u8 = 1;
+    const PUZZLE_NAME: &'static str = "Secret Entrance";
+
+    fn process_data<R: BufRead>(&self, reader: R) -> (u64, u64) {
+        let mut position = Self::START_POSITION;
+        let mut count = 0;
+        let format = format!(
+            "{{[{}{}]}}{{d}}",
+            Self::POSITIVE_SIGN_CHAR,
+            Self::NEGATIVE_SIGN_CHAR
+        );
+        for line in reader.lines().map_while(Result::ok) {
+            if let Ok((sign, distance)) = scan_fmt!(&line, &format, char, i32) {
+                position = (position
+                    + if sign == Self::POSITIVE_SIGN_CHAR {
+                        distance
+                    } else {
+                        -distance
+                    })
+                .rem_euclid(Self::DIAL_SIZE);
+            }
+            if position == Self::COUNT_POSITION {
+                count = count + 1;
+            }
+        }
+        (count, 0)
+    }
+}

tests/examples.rs

@@ -8,6 +8,14 @@ const EXAMPLE_PATHS: &'static [&'static str] = &[
     "../../../data/examples",
 ];
 
+#[test]
+fn secret_entrance() {
+    assert_eq!(
+        Ok((3, 0)),
+        solvers::run_solver(solvers::secret_entrance::SecretEntrance {}, &EXAMPLE_PATHS)
+    );
+}
+
 #[test]
 fn printing_department() {
     assert_eq!(

tests/full_data.rs

@@ -1,5 +1,16 @@
 use advent_of_code_2025::*;
 
+#[test]
+fn secret_entrance() {
+    assert_eq!(
+        Ok((1086, 0)),
+        solvers::run_solver(
+            solvers::secret_entrance::SecretEntrance {},
+            &solvers::DATA_PATHS
+        )
+    );
+}
+
 #[test]
 fn printing_department() {
     assert_eq!(