From 435382031cb8eba35ae3003ac991c6ea714de18b Mon Sep 17 00:00:00 2001 From: Greg Burri Date: Thu, 22 Dec 2022 20:52:44 +0100 Subject: [PATCH] Day 17 part 1 --- src/day17.rs | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++ src/days.rs | 5 +++ src/main.rs | 2 ++ 3 files changed, 102 insertions(+) create mode 100644 src/day17.rs diff --git a/src/day17.rs b/src/day17.rs new file mode 100644 index 0000000..07a145d --- /dev/null +++ b/src/day17.rs @@ -0,0 +1,95 @@ +use std::collections::HashSet; + +#[derive(Debug)] +pub enum Movement { + Left, + Right, +} + +pub fn parse(input: &str) -> Vec { + input + .chars() + .map(|c| match c { + '>' => Movement::Right, + '<' => Movement::Left, + other => panic!("Uknown movement: {}", other), + }) + .collect() +} + +fn rock_collide(pos: (i32, i32), rock: &[(i32, i32)], pile: &HashSet<(i32, i32)>) -> bool { + for (x, y) in rock { + let (x, y) = (x + pos.0, y + pos.1); + if x <= 0 || x >= 8 || y <= 0 || pile.contains(&(x, y)) { + return true; + } + } + false +} + +pub fn height(number_of_rocks: i32, movements: &[Movement]) -> i32 { + let types_of_rock = [ + vec![(0, 0), (1, 0), (2, 0), (3, 0)], // '-'. + vec![(0, 1), (1, 0), (1, 1), (1, 2), (2, 1)], // '+'. + vec![(0, 0), (1, 0), (2, 0), (2, 1), (2, 2)], // '⅃'. + vec![(0, 0), (0, 1), (0, 2), (0, 3)], // '|'. + vec![(0, 0), (0, 1), (1, 0), (1, 1)], // '□'. + ]; + + let mut pile = HashSet::<(i32, i32)>::new(); + let mut current_movement = 0; + let mut highest_point = 0; + for i in 0..number_of_rocks { + let rock = &types_of_rock[i as usize % types_of_rock.len()]; + + let mut pos = (3, highest_point + 4); + loop { + let m = &movements[current_movement]; + current_movement = (current_movement + 1) % movements.len(); + + //println!("Rock: {:?}, pos: {:?}, m: {:?}", rock, pos, m); + + let new_pos = match m { + Movement::Left => (pos.0 - 1, pos.1), + Movement::Right => (pos.0 + 1, pos.1), + }; + + if !rock_collide(new_pos, rock, &pile) { + pos = new_pos; + } + + let new_pos = (pos.0, pos.1 - 1); + if rock_collide(new_pos, rock, &pile) { + let mut h = 0; + for p in rock { + h = h.max(p.1); + pile.insert((p.0 + pos.0, p.1 + pos.1)); + } + + // println!("Rock piled up: {:?}, pos: {:?}", rock, pos); + highest_point = highest_point.max(pos.1 + h); + break; + } + + pos = new_pos + } + } + + highest_point +} + +#[cfg(test)] +mod tests { + use super::*; + + static JET_PATTERN: &str = ">>><<><>><<<>><>>><<<>>><<<><<<>><>><<>>"; + + #[test] + fn part1() { + let movements = parse(JET_PATTERN); + assert_eq!(height(2022, &movements), 3068); + } + + #[test] + fn part2() {} +} diff --git a/src/days.rs b/src/days.rs index bfe185d..4f0a9f9 100644 --- a/src/days.rs +++ b/src/days.rs @@ -169,3 +169,8 @@ pub fn day16() -> String { day16::most_pressure(start, 26, 2, &valves) ) } + +pub fn day17() -> String { + let movements = day17::parse(&fs::read_to_string("data/day17.input").unwrap()); + format!("part1: {}, part2: {}", day17::height(2022, &movements), 0) +} diff --git a/src/main.rs b/src/main.rs index 1086131..c030be0 100644 --- a/src/main.rs +++ b/src/main.rs @@ -19,6 +19,7 @@ mod day13; mod day14; mod day15; mod day16; +mod day17; mod days; #[derive(Parser, Debug)] @@ -51,6 +52,7 @@ fn main() { days::day14, days::day15, days::day16, + days::day17, ]; let args = Args::parse(); -- 2.45.2