diff --git a/.aoc_tiles/tiles/2024/14.png b/.aoc_tiles/tiles/2024/14.png
index c3de62b..e4f0551 100644
Binary files a/.aoc_tiles/tiles/2024/14.png and b/.aoc_tiles/tiles/2024/14.png differ
diff --git a/README.md b/README.md
index bfd468b..983e72b 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
- 2024 - 26 ⭐ - Rust
+ 2024 - 28 ⭐ - Rust
@@ -41,4 +41,7 @@
+
+ 
+
diff --git a/src/day14.rs b/src/day14.rs
new file mode 100644
index 0000000..3e8ac93
--- /dev/null
+++ b/src/day14.rs
@@ -0,0 +1,171 @@
+use aoc_runner_derive::aoc;
+use grid::{AsCoord2d, Coord2d, Grid};
+use regex::Regex;
+use std::str::FromStr;
+
+struct Robot {
+ pos: Coord2d,
+ vel: Coord2d,
+}
+
+#[derive(Debug, Eq, PartialEq)]
+enum Quadrant {
+ NW = 0,
+ NE = 1,
+ SW = 2,
+ SE = 3,
+}
+
+impl FromStr for Robot {
+ type Err = Box;
+ fn from_str(s: &str) -> Result {
+ let re = Regex::new(r"p=(\d+),(\d+) v=([+-]?\d+),([+-]?\d+)").unwrap();
+ match re.captures(s) {
+ Some(c) => Ok(Self {
+ pos: (
+ c.get(1).unwrap().as_str().parse::().unwrap(),
+ c.get(2).unwrap().as_str().parse().unwrap(),
+ )
+ .to_coord(),
+ vel: (
+ c.get(3).unwrap().as_str().parse::().unwrap(),
+ c.get(4).unwrap().as_str().parse().unwrap(),
+ )
+ .to_coord(),
+ }),
+ None => panic!(),
+ }
+ }
+}
+
+impl Robot {
+ fn step(&mut self, bounds: (i64, i64)) {
+ let mut candidate_new_pos = ((self.pos.x() + self.vel.x()), (self.pos.y() + self.vel.y()));
+ if candidate_new_pos.0 < 0 {
+ // if pos goes negative, add the upper bound
+ candidate_new_pos.0 += bounds.0;
+ }
+ if candidate_new_pos.1 < 0 {
+ candidate_new_pos.1 += bounds.1;
+ }
+ candidate_new_pos.0 %= bounds.0;
+ candidate_new_pos.1 %= bounds.1;
+
+ self.pos = candidate_new_pos.to_coord();
+ }
+ fn quad(&self, bounds: (i64, i64)) -> Option {
+ let splits = (bounds.0 / 2, bounds.1 / 2);
+ if self.pos.x() < splits.0 && self.pos.y() < splits.1 {
+ Some(Quadrant::NW)
+ } else if self.pos.x() > splits.0 && self.pos.y() < splits.1 {
+ Some(Quadrant::NE)
+ } else if self.pos.x() < splits.0 && self.pos.y() > splits.1 {
+ Some(Quadrant::SW)
+ } else if self.pos.x() > splits.0 && self.pos.y() > splits.1 {
+ Some(Quadrant::SE)
+ } else {
+ None
+ }
+ }
+}
+
+#[allow(dead_code)]
+fn display(robots: &Vec, bounds: (i64, i64)) {
+ let grid = as_grid(robots, bounds);
+ for row in 0..grid.height() {
+ for col in 0..grid.width() {
+ print!(
+ "{}",
+ if *grid.get(&(col, row)).unwrap() != 0 {
+ "█"
+ } else {
+ " "
+ }
+ );
+ }
+ println!(" EOL");
+ }
+}
+
+fn as_grid(robots: &Vec, bounds: (i64, i64)) -> Grid {
+ let mut grid = Grid::with_shape(bounds.0 as usize, bounds.1 as usize, 0);
+ for r in robots {
+ grid.increment(&r.pos, 1usize);
+ }
+ grid
+}
+
+fn parse(input: &str) -> Vec {
+ input.lines().map(|l| l.parse().unwrap()).collect()
+}
+
+fn part1_impl(input: &str, width: i64, height: i64) -> u64 {
+ let mut robots = parse(input);
+ for _ in 0..100 {
+ for r in &mut robots {
+ r.step((width, height))
+ }
+ }
+ let mut counts = [0; 4];
+ for r in robots {
+ if let Some(q) = r.quad((width, height)) {
+ counts[q as usize] += 1
+ }
+ }
+ counts.iter().product()
+}
+
+#[aoc(day14, part1)]
+pub fn part1(input: &str) -> u64 {
+ part1_impl(input, 101, 103)
+}
+
+#[aoc(day14, part2)]
+pub fn part2(input: &str) -> u64 {
+ let width = 101;
+ let height = 103;
+ let mut robots = parse(input);
+ for i in 1.. {
+ for r in &mut robots {
+ r.step((width, height))
+ }
+ // collect into lines
+ let g = as_grid(&robots, (width, height));
+ if g.data
+ .chunk_by(|a, b| *a != 0 && *b != 0)
+ .filter(|c| !c.is_empty() && c[0] != 0)
+ .any(|c| c.len() > width as usize / 10)
+ {
+ return i;
+ }
+ }
+ unreachable!()
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ const EXAMPLE: &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 part1_example() {
+ assert_eq!(part1_impl(EXAMPLE, 11, 7), 12);
+ }
+
+ // part 2 does not converge using the test vector
+ // #[test]
+ // fn part2_example() {
+ // // assert_eq!(part2(EXAMPLE), 0);
+ // }
+}
diff --git a/src/lib.rs b/src/lib.rs
index e77ce9c..7b521e4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,11 @@
use aoc_runner_derive::aoc_lib;
pub mod day1;
+pub mod day10;
+pub mod day11;
+pub mod day12;
+pub mod day13;
+pub mod day14;
pub mod day2;
pub mod day3;
pub mod day4;
@@ -9,9 +14,5 @@ pub mod day6;
pub mod day7;
pub mod day8;
pub mod day9;
-pub mod day10;
-pub mod day11;
-pub mod day12;
-pub mod day13;
aoc_lib! { year = 2024 }
diff --git a/utils/grid/lib.rs b/utils/grid/lib.rs
index f27f5ab..9e56c96 100644
--- a/utils/grid/lib.rs
+++ b/utils/grid/lib.rs
@@ -3,7 +3,7 @@ use std::{
io::{BufRead, Cursor},
iter::repeat,
mem::swap,
- ops::{Add, Sub},
+ ops::{Add, AddAssign, Sub},
str::FromStr,
};
@@ -51,6 +51,18 @@ impl AsCoord2d for Coord2d {
}
}
+impl AsCoord2d for &Coord2d {
+ fn to_coord(self) -> Coord2d {
+ self.to_owned()
+ }
+ fn x(&self) -> i64 {
+ self.x
+ }
+ fn y(&self) -> i64 {
+ self.y
+ }
+}
+
impl AsCoord2d for (i32, i32) {
fn to_coord(self) -> Coord2d {
Coord2d {
@@ -178,6 +190,18 @@ impl Grid {
None => None,
}
}
+ pub fn increment<'a, A, C: AsCoord2d>(&'a mut self, c: &C, i: A) -> Option<&'a T>
+ where
+ T: AddAssign,
+ {
+ match self.valid_pos(c) {
+ Some(pos) => {
+ self.data[pos] += i;
+ Some(&self.data[pos])
+ }
+ None => None,
+ }
+ }
pub fn row(&self, y: i64) -> Option<&[T]> {
if y < self.height() as i64 {
Some(&self.data[self.pos(&(0, y)) as usize..self.pos(&(self.width, y)) as usize])
@@ -300,7 +324,10 @@ FBCG";
fn from_string() {
let grid = unchecked_load();
assert_eq!(grid.data, "ABCDEFGHIJKLFBCG".as_bytes());
- assert_eq!(TEST_VECTOR_S.parse::>().unwrap().data, "ABCDEFGHIJKLFBCG".as_bytes());
+ assert_eq!(
+ TEST_VECTOR_S.parse::>().unwrap().data,
+ "ABCDEFGHIJKLFBCG".as_bytes()
+ );
}
#[test]