Add day 1 (rough version)

bram/rust/Cargo.toml

@@ -5,3 +5,4 @@ edition = "2024"
 
 [dependencies]
 colored = "3.0.0"
+regex = "1.12.2"

bram/rust/src/day_01/mod.rs

@@ -1,5 +1,75 @@
 use crate::utils;
+use regex::Regex;
+
+struct Dial {
+    points_at : i16,
+    clicks : u32,
+    passing_clicks : u32,
+}
+impl Dial {
+    fn new() -> Dial {
+        Dial { points_at : 50, clicks : 0, passing_clicks : 0 }
+    }
+
+    fn rotate_by(&mut self, r : i16) -> () {
+        let start : i16 = self.points_at;
+
+        self.points_at += r;
+        self.points_at = self.points_at.rem_euclid(100);
+        self.passing_clicks += (r.abs() / 100) as u32;
+
+        if self.points_at == 0 {
+            self.clicks += 1;
+
+            // Avoid double counting when starting and landing on zero
+            if r / 100 != 0 && r % 100 == 0 {
+                self.passing_clicks -= 1;
+            }
+        }
+
+        if r < 0 && start < self.points_at && start != 0 {
+            self.passing_clicks += 1;
+        }
+        if r > 0 && start > self.points_at && self.points_at != 0 {
+            self.passing_clicks += 1;
+        }
+
+        // println!(
+        //     "Dial {} now points at {} ({} clicks, {} passing)",
+        //     r, self.points_at, self.clicks, self.passing_clicks
+        // );
+    }
+}
 
 pub fn answer(text : String) ->( u32, u32 ) {
-    ( 0, 0 )
+    let items : Vec<i16> = parse(text);
+
+    let mut dial : Dial = Dial::new();
+    for d in items.iter() {
+        dial.rotate_by(*d);
+    }
+
+    println!("Length: {}", &items.len());
+
+    ( dial.clicks
+    , dial.clicks + dial.passing_clicks
+    // 5978 too low
+    // 6298 too low
+    // 6536 too high
+    )
+}
+
+fn parse(text : String) -> Vec<i16> {
+    Regex::new(r"(L|R)(\d+)").unwrap()
+        .captures_iter(&text)
+        .map(|c| c.extract())
+        .filter_map(
+            |(_, [ d, n ])|
+            match d {
+                "L" => Some(-1 * utils::str_to_i16(n)?),
+                "R" => utils::str_to_i16(n),
+                _ => None,
+            }
+        )
+        .collect()
 }

bram/rust/src/utils/mod.rs

@@ -16,6 +16,10 @@ pub fn read_from_file(name : &str) -> String {
     }
 }
 
+pub fn str_to_i16(s : &str) -> Option<i16> {
+    s.trim().to_string().parse::<i16>().ok()
+}
+
 pub fn str_to_i32(s : &str) -> Option<i32> {
     s.trim().to_string().parse::<i32>().ok()
 }
@@ -23,6 +27,10 @@ pub fn str_to_i32(s : &str) -> Option<i32> {
 pub fn str_to_u8(s : &str) -> Option<u8> {
     s.trim().to_string().parse::<u8>().ok()
 }
+
+pub fn str_to_u16(s : &str) -> Option<u16> {
+    s.trim().to_string().parse::<u16>().ok()
+}
     
 pub fn str_to_u32(s : &str) -> Option<u32> {
     s.trim().to_string().parse::<u32>().ok()