solve: day1

Author: tom-anders

Cargo.toml

@@ -2,7 +2,7 @@
 resolver = "2"
 members = [
     "aoc_lib/aoc_derive",
-    "aoc_lib/utils",
+    "aoc_lib/utils", "day1",
 ]
 
 [workspace.dependencies]

day1/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "day1"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+aoc_derive.path = '../aoc_lib/aoc_derive'
+utils.path = '../aoc_lib/utils'
+derive_more.workspace = true
+itertools.workspace = true
+lazy-regex.workspace = true
+parse-display.workspace = true
+rayon.workspace = true
+regex.workspace = true
+num.workspace = true
+
+[dev-dependencies]
+pretty_assertions.workspace = true

day1/src/main.rs

@@ -0,0 +1,57 @@
+use aoc_derive::aoc_main;
+use utils::*;
+
+#[aoc_main]
+fn solve(input: Input) -> impl Into<Solution> {
+    let (_, password, password2) =
+        input.lines().fold((50, 0, 0), |(dial, password, password2), line| {
+            let inc = if line.starts_with('L') { -1 } else { 1 };
+            let steps: i64 = line[1..].parse().unwrap();
+
+            let (dial, password2) =
+                (0..steps).fold((dial, password2), |(dial, password2), _| match dial + inc {
+                    0 => (0, password2 + 1),
+                    100 => (0, password2 + 1),
+                    -1 => (99, password2),
+                    next => (next, password2),
+                });
+            let password = if dial == 0 { password + 1 } else { password };
+
+            (dial, password, password2)
+        });
+    (password, password2)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_examples() {
+        use utils::assert_example;
+        assert_part2!("R1000", 10);
+        assert_part2!("L1000", 10);
+        assert_part2!("R50", 1);
+        assert_part2!("L50", 1);
+
+        assert_example!(
+            r#"R49
+R1"#,
+            1
+        );
+
+        assert_example!(
+            r#"L68
+L30
+R48
+L5
+R60
+L55
+L1
+L99
+R14
+L82"#,
+            3,
+            6
+        );
+    }
+}