Day14 - part 1

diff --git a/src/day14.rs b/src/day14.rs
new file mode 100644 (file)
index 0000000..6b9f03b
--- /dev/null
+++ b/src/day14.rs
@@ -0,0 +1,141 @@
+use std::error::Error;
+use std::path::Path;
+
+const HEIGHT: i32 = 103;
+const WIDTH: i32 = 101;
+
+#[derive(Debug)]
+struct Robot {
+    pos: (i32, i32),
+    speed: (i32, i32),
+}
+
+impl Robot {
+    pub fn new(pos: (i32, i32), speed: (i32, i32)) -> Self {
+        Self { pos, speed }
+    }
+}
+
+struct Puzzle {
+    robots: Vec<Robot>,
+    height: i32,
+    width: i32,
+}
+
+impl Puzzle {
+    pub fn new(input: &str, height: i32, width: i32) -> Self {
+        let mut robots: Vec<Robot> = Vec::new();
+        input.lines()
+            .for_each(|l| {
+                let (start, speed) = l.split_once(" ").unwrap();
+
+                let start = start[2..start.len()].split_once(",").unwrap();
+                let start = (start.0.parse::<i32>().unwrap(), start.1.parse::<i32>().unwrap());
+
+                let speed = speed[2..speed.len()].split_once(",").unwrap();
+                let speed = (speed.0.parse::<i32>().unwrap(), speed.1.parse::<i32>().unwrap());
+
+                robots.push(Robot::new(start, speed));
+            });
+        Self { robots, height, width }
+    }
+
+    fn update_by(&mut self, seconds: i32) {
+        self.robots.iter_mut()
+            .for_each(|r| {
+                let (mut x, mut y) = r.pos;
+                let (vx, vy) = r.speed;
+                x = (x + vx*seconds) % self.width;
+                y = (y + vy*seconds) % self.height;
+                if x < 0 {
+                    x += self.width;
+                }
+                if y < 0 {
+                    y += self.height;
+                }
+                r.pos = (x, y);
+            });
+    }
+
+    fn safety_factor(&self) -> u32 {
+        let mut c = (0, 0, 0, 0);
+        self.robots.iter()
+            .for_each(|r| {
+                if r.pos.0 < self.width / 2 && r.pos.1 < self.height / 2 {
+                    c.0 += 1;
+                }
+                else if r.pos.0 > self.width / 2 && r.pos.1 < self.height / 2 {
+                    c.1 += 1;
+                }
+                else if r.pos.0 < self.width / 2 && r.pos.1 > self.height / 2 {
+                    c.2 += 1;
+                }
+                else if r.pos.0 > self.width / 2 && r.pos.1 > self.height / 2 {
+                    c.3 += 1;
+                }
+            });
+
+        c.0 * c.1 * c.2 * c.3
+    }
+}
+
+fn run_part1(input: &str) -> Result<u32, Box<dyn Error>> {
+    println!("Running {} - part 1", get_day());
+
+    let mut puzzle = Puzzle::new(input, HEIGHT, WIDTH);
+    puzzle.update_by(100);
+
+    Ok(puzzle.safety_factor())
+}
+
+fn run_part2(input: &str) -> Result<u32, Box<dyn Error>> {
+    println!("Running {} - part 2", get_day());
+
+    Ok(0)
+}
+
+pub fn run(input: &str) -> Result<(), Box<dyn Error>> {
+    let res = run_part1(input)?;
+    println!("{res}");
+
+    let res = run_part2(input)?;
+    println!("{res}");
+
+    Ok(())
+}
+
+fn get_day() -> String {
+    let filename = file!();
+    Path::new(filename).file_stem().unwrap().to_str().unwrap().to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    static TEXT_INPUT: &str = "\
+p=0,4 v=3,-3
+p=6,3 v=-1,-3
+p=10,3 v=-1,2
+p=2,0 v=2,-1
+p=0,0 v=1,3
+p=3,0 v=-2,-2
+p=7,6 v=-1,-3
+p=3,0 v=-1,-2
+p=9,3 v=2,3
+p=7,3 v=-1,2
+p=2,4 v=2,-3
+p=9,5 v=-3,-3";
+
+    #[test]
+    fn test_part1() {
+        let mut puzzle = Puzzle::new(TEXT_INPUT, 7, 11);
+        puzzle.update_by(100);
+        assert_eq!(12, puzzle.safety_factor());
+    }
+
+    #[test]
+    fn test_part2() {
+        assert_eq!(0, run_part2(TEXT_INPUT).unwrap());
+    }
+}

diff --git a/src/main.rs b/src/main.rs
index 9f925bf18c1c54a51488770e4564964fc6d1bc20..d015b9042c2df0d6aaebacd0f85aa285c35f1463 100644 (file)
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,6 +17,7 @@ pub mod day10;
 pub mod day11;
 pub mod day12;
 pub mod day13;
+pub mod day14;
 
 fn main() {
     let args: Vec<String> = env::args().collect();
@@ -52,6 +53,7 @@ fn run(day: &str, input_file: &str) -> Result<(), Box<dyn Error>> {
         "day11" => day11::run(&input)?,
         "day12" => day12::run(&input)?,
         "day13" => day13::run(&input)?,
+        "day14" => day14::run(&input)?,
         _ => return Err(format!("unknown or unimplemented day \"{day}\"").into()),
     }
     Ok(())