3 files changed, 141 insertions(+), 0 deletions(-)

A input/day14/example
A src/day14/mod.rs
M src/main.rs

@@ 0,0 1,12 @@
+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

@@ 0,0 1,121 @@
+use std::{
+    fs::File,
+    io::{BufRead, BufReader},
+    path::Path,
+};
+
+pub fn solve(input: &Path) -> anyhow::Result<()> {
+    println!("part one: {}", part_one(input)?);
+    //println!("part two: {}", part_two(input)?);
+
+    Ok(())
+}
+
+#[derive(Debug)]
+struct R {
+    p: P<usize>,
+    v: P<i32>,
+}
+
+impl R {
+    fn from_str(line: &str) -> Self {
+        let mut split = line.split_whitespace();
+        let mut p_split = split.next().unwrap()[2..].split(",");
+        let mut v_split = split.next().unwrap()[2..].split(",");
+        Self {
+            p: P {
+                x: p_split.next().unwrap().parse().unwrap(),
+                y: p_split.next().unwrap().parse().unwrap(),
+            },
+            v: P {
+                x: v_split.next().unwrap().parse().unwrap(),
+                y: v_split.next().unwrap().parse().unwrap(),
+            },
+        }
+    }
+}
+
+#[derive(Debug)]
+struct P<T> {
+    x: T,
+    y: T,
+}
+
+fn _print_robots_on_map(robots: &[R], w: usize, h: usize, q: bool) {
+    for y in 0..h {
+        if q && y == h / 2 {
+            println!();
+            continue;
+        }
+        for x in 0..w {
+            if q && x == w / 2 {
+                print!(" ");
+                continue;
+            }
+            let robots_on_tile = robots.iter().filter(|r| r.p.x == x && r.p.y == y).count();
+            if robots_on_tile > 0 {
+                print!("{}", robots_on_tile);
+            } else {
+                //print!(".");
+                print!(" ");
+            }
+        }
+        println!();
+    }
+}
+
+fn part_one(input: &Path) -> anyhow::Result<usize> {
+    let reader = BufReader::new(File::open(input)?);
+
+    let mut robots: Vec<R> = vec![];
+    for line in reader.lines() {
+        robots.push(R::from_str(&line?));
+    }
+
+    //let (w, h) = (11, 7);
+    let (w, h) = (101, 103);
+
+    //print_robots_on_map(&robots, w, h, false);
+    for _ in 0..100 {
+        //for i in 0..10403 {
+        for robot in &mut robots {
+            let mut nx: i32 = robot.p.x as i32 + robot.v.x;
+            if nx >= w as i32 {
+                nx = (nx - w as i32).abs();
+            } else if nx < 0 {
+                nx = (nx + w as i32).abs();
+            }
+            let mut ny: i32 = robot.p.y as i32 + robot.v.y;
+            if ny >= h as i32 {
+                ny = (ny - h as i32).abs();
+            } else if ny < 0 {
+                ny = (ny + h as i32).abs();
+            }
+            robot.p.x = nx as usize;
+            robot.p.y = ny as usize;
+        }
+        //println!();
+        //print_robots_on_map(&robots, w, h, true);
+    }
+    //println!();
+    //print_robots_on_map(&robots, w, h, true);
+
+    let q1 = robots
+        .iter()
+        .filter(|r| r.p.x < w / 2 && r.p.y < h / 2)
+        .count();
+    let q2 = robots
+        .iter()
+        .filter(|r| r.p.x > w / 2 && r.p.y < h / 2)
+        .count();
+    let q3 = robots
+        .iter()
+        .filter(|r| r.p.x > w / 2 && r.p.y > h / 2)
+        .count();
+    let q4 = robots
+        .iter()
+        .filter(|r| r.p.x < w / 2 && r.p.y > h / 2)
+        .count();
+
+    Ok(q1 * q2 * q3 * q4)
+}

@@ 7,6 7,7 @@ mod day10;
 mod day11;
 mod day12;
 mod day13;
+mod day14;
 mod day2;
 mod day3;
 mod day4;


@@ 76,6 77,10 @@ enum DayArgs {
         #[arg(short)]
         input: PathBuf,
     },
+    Day14 {
+        #[arg(short)]
+        input: PathBuf,
+    },
 }
 
 fn main() -> anyhow::Result<()> {


@@ 121,6 126,9 @@ fn main() -> anyhow::Result<()> {
         DayArgs::Day13 { input } => {
             day13::solve(&input)?;
         }
+        DayArgs::Day14 { input } => {
+            day14::solve(&input)?;
+        }
     }
 
     Ok(())