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//use std::{thread::{sleep}, time::Duration};
const ROCK: char = '#';
const AIR: char = '.';
type Grid = Vec<Vec<char>>;
#[derive(Debug,Clone,PartialEq)]
struct Pos {
x: i32,
y: i32,
}
impl Pos {
fn new(x:i32,y:i32) -> Pos {
Pos{x, y}
}
fn translate(&self, other: &Pos) -> Pos {
Pos{x: self.x+other.x, y: self.y+other.y}
}
}
/*
####
.#.
###
.#.
..#
..#
###
#
#
#
#
##
##
*/
#[derive(Debug,Clone,PartialEq)]
enum RockType {
Bar,Cross,Ell,VBar,Square
}
impl RockType {
fn points(&self) -> Vec<Pos> {
match self {
Self::Bar => vec![Pos::new(0,0), Pos::new(1,0), Pos::new(2,0), Pos::new(3,0)],
Self::Cross => vec![Pos::new(1,0), Pos::new(0,1), Pos::new(1,1), Pos::new(2,1), Pos::new(1,2)],
Self::Ell => vec![Pos::new(0,0), Pos::new(1,0), Pos::new(2,0), Pos::new(2,1), Pos::new(2,2)],
Self::VBar => vec![Pos::new(0,0), Pos::new(0,1), Pos::new(0,2), Pos::new(0,3)],
Self::Square => vec![Pos::new(0,0), Pos::new(0,1), Pos::new(1,0), Pos::new(1,1)],
}
}
}
#[derive(Debug,Clone,PartialEq)]
enum Direction {
Down,Left,Right
}
impl Direction {
fn unit(&self)->Pos {
match self {
Self::Down => Pos{x:0, y:-1},
Self::Left => Pos{x:-1, y:0},
Self::Right => Pos{x:1, y:0},
}
}
}
#[derive(Debug,Clone,PartialEq)]
struct Rock {
rtype: RockType,
pos: Pos, // Position of lower left point in formation
}
impl Rock {
fn points(&self) -> Vec<Pos> {
self.rtype.points()
.into_iter().map(|p| {p.translate(&self.pos)}).collect()
}
pub fn mv(self, dir: Direction, grid: &Grid) -> Result<Self,Self> {
let width: i32 = grid[0].len() as i32;
let du = dir.unit();
let np: Vec<Pos> = self.points().into_iter().map(|p| {p.translate(&du)}).collect();
if np.iter().any(|p| {
// Bounds check
p.y < 0 ||
p.x < 0 ||
p.x >= width ||
// Intersecting another rock?
grid[p.y as usize][p.x as usize] != AIR
}) {
Err(self)
} else {
let mut nr = self.clone();
nr.pos = self.pos.translate(&du);
Ok(nr)
}
}
pub fn solidify(self, grid: &mut Vec<Vec<char>>) {
for pt in self.points() {
grid[pt.y as usize][pt.x as usize] = ROCK;
}
}
}
fn rock_height(grid: &Grid) -> usize {
grid.iter().enumerate()
.rfind(|row| {
row.1.iter().any(|cell| {*cell == ROCK})
})
.map(|row| {
row.0+1 // height is one more than the index..
})
.unwrap_or(0)
}
// fn print(grid: &Grid, rock: &Rock, rock_count: usize) {
// print!("{}[2J", 27 as char); // clear terminal!
// println!("+++++++");
// let pts = rock.points();
// for (y ,row) in grid.iter().enumerate().rev() {
// for (x, cell) in row.iter().enumerate() {
// if pts.contains(&Pos{x:(x as i32),y:(y as i32)}) {
// print!("@");
// } else {
// print!("{}", cell);
// }
// }
// print!("\n");
// }
// println!("+++++++ height: {} rocks: {}", rock_height(grid), rock_count);
// }
pub fn run(input: String) {
let initial_height = 6;
let width = 7;
let mut rocks = vec![RockType::Bar,RockType::Cross,RockType::Ell,RockType::VBar,RockType::Square].into_iter().cycle();
let mut gas_jets = input.chars().cycle();
let mut grid: Grid = (0..initial_height).map(|_| {
(0..width).map(|_| {AIR}).collect()
}).collect();
let mut rock = Rock{
rtype: rocks.next().unwrap(),
pos: Pos{x: 2, y: 3}
};
let mut rocks_count: usize = 1;
'lp: loop {
let push = match gas_jets.next().unwrap() {
'>' => Direction::Right,
'<' => Direction::Left,
dir => panic!("Unexpected jet direction! {}", dir)
};
// apply jet, ignore any error.
rock = rock.mv(push, &grid).unwrap_or_else(|e| {e});
// apply gravity
rock = match rock.mv(Direction::Down, &grid) {
Ok(rr) => rr, // Complete the move!
Err(rr) => {
// We didn't move, solidify!
rr.solidify(&mut grid);
if rocks_count == 2022 {
break 'lp;
}
// Measure height...
let max_rock = rock_height(&grid);
// Extend grid to max_rock + 7 (enough room for any new rocks at a height of at least 3 over the old ones)
let ext = (max_rock+7)-grid.len();
if ext > 0 {
grid.extend((0..ext).map(|_| { (0..width).map(|_| { AIR }).collect() }));
}
// remember how many rocks we did
rocks_count += 1;
// Spawn new rock
Rock {
rtype: rocks.next().unwrap(),
pos: Pos{x: 2, y: max_rock as i32 +3 }
}
}
};
//print(&grid, &rock, rocks_count);
//sleep(Duration::from_millis(100));
}
println!("Day 17: {}", rock_height(&grid));
}
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