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

2026-01-26 22:01:52 +01:00
parent 8f9356e81e
commit b5665199e1
8 changed files with 126 additions and 1 deletions
@@ -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)
+    }
+}