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day(14): refactor

Signed-off-by: Matej Focko <mfocko@redhat.com>
This commit is contained in:
Matej Focko 2022-12-14 15:47:56 +01:00
parent 6789a40038
commit 2ac9103fe2
Signed by: mfocko
GPG key ID: 7C47D46246790496

View file

@ -103,6 +103,35 @@ fn can_move(grain: &Coord, lines: &[Line], set: &BTreeSet<Coord>) -> Option<Coor
None None
} }
fn simulate_falling<F>(lines: &Input, terminate: F) -> usize
where
F: Fn(&Coord, &Input, &BTreeSet<Coord>, bool) -> bool
{
let mut grains: VecDeque<Coord> = VecDeque::new();
let mut set_grains: BTreeSet<Coord> = BTreeSet::new();
loop {
for i in (0..grains.len()).rev() {
let grain = grains[i];
let mut is_set = false;
if let Some(new_grain) = can_move(&grain, lines, &set_grains) {
grains[i] = new_grain;
} else {
let grain = grains.pop_back().unwrap();
set_grains.insert(grain);
is_set = true;
}
if terminate(&grain, lines, &set_grains, is_set) {
return set_grains.len();
}
}
grains.push_front(Coord::new(500, 0));
}
}
struct Day14; struct Day14;
impl Solution<Input, Output> for Day14 { impl Solution<Input, Output> for Day14 {
fn parse_input<P: AsRef<Path>>(pathname: P) -> Input { fn parse_input<P: AsRef<Path>>(pathname: P) -> Input {
@ -113,65 +142,31 @@ impl Solution<Input, Output> for Day14 {
} }
fn part_1(input: &Input) -> Output { fn part_1(input: &Input) -> Output {
let mut grains: VecDeque<Coord> = VecDeque::new(); fn terminate(grain: &Coord, lines: &Input, set_grains: &BTreeSet<Coord>, _is_set: bool) -> bool {
let mut set_grains: BTreeSet<Coord> = BTreeSet::new(); free_falling(grain, lines, set_grains)
loop {
for i in (0..grains.len()).rev() {
let grain = &mut grains[i];
if free_falling(grain, input, &set_grains) {
return set_grains.len();
}
if let Some(new_grain) = can_move(grain, input, &set_grains) {
*grain = new_grain;
} else {
let grain = grains.pop_back().unwrap();
set_grains.insert(grain);
}
}
grains.push_front(Coord::new(500, 0));
} }
simulate_falling(input, terminate)
} }
fn part_2(input: &Input) -> Output { fn part_2(input: &Input) -> Output {
let mut lines = input.clone(); fn terminate(grain: &Coord, _lines: &Input, _set_grains: &BTreeSet<Coord>, is_set: bool) -> bool {
let y = lines is_set && grain == &Coord::new(500, 0)
}
let y = input
.iter() .iter()
.map(|l| max(l.from.y(), l.to.y())) .map(|l| max(l.from.y(), l.to.y()))
.max() .max()
.unwrap(); .unwrap();
let mut lines = input.clone();
lines.push(Line { lines.push(Line {
from: Coord::new(500 - 2 * (*y + 2), *y + 2), from: Coord::new(500 - (*y + 2), *y + 2),
to: Coord::new(500 + 2 * (*y + 2), *y + 2), to: Coord::new(500 + (*y + 2), *y + 2),
}); });
let mut grains: VecDeque<Coord> = VecDeque::new(); simulate_falling(&lines, terminate)
let mut set_grains: BTreeSet<Coord> = BTreeSet::new();
loop {
// debug!("Grains setting: {:?}, set grains: {:?}", grains.len(), set_grains.len());
for i in (0..grains.len()).rev() {
let grain = &mut grains[i];
if let Some(new_grain) = can_move(grain, &lines, &set_grains) {
*grain = new_grain;
} else {
let grain = grains.pop_back().unwrap();
set_grains.insert(grain);
// debug!("Set grain {:?}", grain);
if grain == Coord::new(500, 0) {
return set_grains.len();
}
}
}
grains.push_front(Coord::new(500, 0));
}
} }
} }