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#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
pub struct Map {
grid: Grid<bool>,
generator: (Row, Col),
abyss: Row,
sand_count: usize,
}
impl Map {
fn filled(&self, pos: (Row, Col), floor: bool) -> bool {
self.grid[pos.0][pos.1] || (floor && (pos.0 > self.abyss))
}
fn fill(&mut self, pos: (Row, Col)) {
self.grid[pos.0][pos.1] = true;
}
fn drop(&mut self, floor: bool) -> bool {
let mut pos = self.generator;
if self.filled(pos, floor) {
if floor {
return true;
} else {
panic!("generator filled but no floor");
}
}
loop {
if !floor && pos.0 + 1 >= self.abyss {
return true;
}
let mut can_fall = false;
for next in [
(pos.0 + 1, pos.1),
(pos.0 + 1, pos.1 - 1),
(pos.0 + 1, pos.1 + 1),
] {
if !self.filled(next, floor) {
pos = next;
can_fall = true;
break;
}
}
if !can_fall {
break;
}
}
self.fill(pos);
self.sand_count += 1;
false
}
}
pub fn parse(fh: File) -> Result<Map> {
let mut grid = Grid::default();
for line in parse::raw_lines(fh) {
let coords: Vec<_> = line
.split(" -> ")
.map(|pos| {
let mut parts = pos.split(',');
let col = parts.next().unwrap();
let row = parts.next().unwrap();
(Row(row.parse().unwrap()), Col(col.parse().unwrap()))
})
.collect();
for pair in coords.windows(2) {
let (row, col) = pair[0];
let (next_row, next_col) = pair[1];
grid.grow(row + 1, col + 1);
grid.grow(next_row + 1, next_col + 1);
if row == next_row {
for col in
(col.0.min(next_col.0)..=col.0.max(next_col.0)).map(Col)
{
grid[row][col] = true;
}
} else if col == next_col {
for row in
(row.0.min(next_row.0)..=row.0.max(next_row.0)).map(Row)
{
grid[row][col] = true;
}
} else {
panic!("diagonal line?");
}
}
}
let abyss = grid.rows();
grid.grow(grid.rows() + grid.rows().0, grid.cols() + grid.cols().0);
Ok(Map {
grid,
generator: (Row(0), Col(500)),
abyss,
sand_count: 0,
})
}
pub fn part1(mut map: Map) -> Result<usize> {
loop {
let abyss = map.drop(false);
if abyss {
return Ok(map.sand_count);
}
}
}
pub fn part2(mut map: Map) -> Result<usize> {
loop {
let blocked = map.drop(true);
if blocked {
return Ok(map.sand_count);
}
}
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2022, 14).unwrap()).unwrap()).unwrap(),
737
);
assert_eq!(
part2(parse(parse::data(2022, 14).unwrap()).unwrap()).unwrap(),
28145
);
}
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