diff options
| -rw-r--r-- | 2025/09/rust/src/main.rs | 51 |
1 files changed, 44 insertions, 7 deletions
diff --git a/2025/09/rust/src/main.rs b/2025/09/rust/src/main.rs index 0a60ece..8c13bcb 100644 --- a/2025/09/rust/src/main.rs +++ b/2025/09/rust/src/main.rs @@ -1,5 +1,44 @@ use std::io; +#[derive(Debug)] +struct Floor { + x_comp: Vec<usize>, + y_comp: Vec<usize>, +} + +impl Floor { + fn new(pts: Vec<(usize, usize)>) -> (Self, Vec<(usize, usize)>) { + let (mut xs, mut ys): (Vec<_>, Vec<_>) = pts.clone().into_iter().unzip(); + xs.sort_unstable(); + xs.dedup(); + ys.sort_unstable(); + ys.dedup(); + + let pts = pts + .into_iter() + .map(|(x, y)| (xs.binary_search(&x).unwrap(), ys.binary_search(&y).unwrap())) + .collect(); + + ( + Self { + x_comp: xs, + y_comp: ys, + }, + pts, + ) + } + + fn uncomp(self: &Self, (x, y): (usize, usize)) -> (usize, usize) { + (self.x_comp[x], self.y_comp[y]) + } + + fn area(self: &Self, p1: (usize, usize), p2: (usize, usize)) -> usize { + let (x1, y1) = self.uncomp(p1); + let (x2, y2) = self.uncomp(p2); + (x1.abs_diff(x2) + 1) * (y1.abs_diff(y2) + 1) + } +} + fn main() { let pts = io::stdin() .lines() @@ -8,12 +47,14 @@ fn main() { let (x, y) = line.split_once(',').unwrap(); (x.parse().unwrap(), y.parse().unwrap()) }) - .collect::<Vec<(u64, u64)>>(); + .collect::<Vec<(usize, usize)>>(); + + let (floor, pts) = Floor::new(pts); - let silver: u64 = pts + let silver: usize = pts .iter() .enumerate() - .flat_map(|(idx, p1)| pts.iter().take(idx).map(move |p2| area(*p1, *p2))) + .flat_map(|(idx, p1)| pts.iter().take(idx).map(|p2| floor.area(*p1, *p2))) .max() .unwrap(); @@ -21,7 +62,3 @@ fn main() { println!("silver: {silver}"); println!("gold: {gold}"); } - -fn area((x1, y1): (u64, u64), (x2, y2): (u64, u64)) -> u64 { - (x1.abs_diff(x2) + 1) * (y1.abs_diff(y2) + 1) -} |