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2022 day 16 refactor

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This commit is contained in:
Maciej Jur 2022-12-17 12:32:39 +01:00
parent e3321a08a8
commit a581dd4f44
1 changed files with 37 additions and 21 deletions
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58
2022/rust/src/solutions/day16.rs
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@ -99,49 +99,65 @@ fn release_bitmap(valves: &[Valve], bitmap: u64) -> u32 {
sum sum
} }
// fn set_to_bitmap(set: &HashSet<usize>) -> u64 { fn set_to_bitmap(set: &HashSet<usize>) -> u64 {
// let mut map = 0; let mut map = 0;
// for &index in set { for &index in set {
// map |= 1 << index map |= 1 << index
// } }
// map map
// } }
struct MoveState<'a> { struct MoveState<'a> {
curr: usize, current: usize,
next: usize,
time_left: u32, time_left: u32,
closed: &'a HashSet<usize>, closed: &'a HashSet<usize>,
} }
impl<'a> MoveState<'a> {
fn as_cache_key(&self) -> (usize, u32, u64) {
(self.current, self.time_left, set_to_bitmap(self.closed))
}
}
fn move_to_open( fn move_to_open(
valves: &[Valve], valves: &[Valve],
distances: &HashMap<(usize, usize), u32>, distances: &HashMap<(usize, usize), u32>,
state: MoveState, state: MoveState,
cache: &mut HashMap<(usize, u32, u64), u32>
) -> u32 { ) -> u32 {
let distance = state.time_left.min(*distances.get(&(state.curr, state.next)).unwrap()); if state.time_left < 1 { return 0 };
if distance == state.time_left { return 0 }; let cached = cache.get(&state.as_cache_key());
let curr = state.next; if cached.is_some() { return *cached.unwrap() }
let closed = { let mut closed = state.closed.clone(); closed.remove(&curr); closed }; let closed = { let mut closed = state.closed.clone(); closed.remove(&state.current); closed };
let time_left = state.time_left - distance - 1; let time_left = state.time_left - 1;
let released = valves[curr].rate * time_left; let released = valves[state.current].rate * time_left;
let max_next = closed.iter() let max_next = closed.iter()
.map(|&next| move_to_open(valves, distances, MoveState { curr, next, time_left, closed: &closed })) .filter_map(|&current| {
let distance = distances[&(state.current, current)];
match time_left > distance + 1 {
true => Some(move_to_open(valves, distances, MoveState {
current,
time_left: time_left - distance,
closed: &closed
}, cache)),
false => None,
}
})
.max() .max()
.unwrap_or_default(); .unwrap_or_default();
let result = released + max_next;
released + max_next cache.insert(state.as_cache_key(), result);
result
} }
fn find_max_for_start(valves: &[Valve], start: usize, limit: u32) -> u32 { fn find_max_for_start(valves: &[Valve], start: usize, limit: u32) -> u32 {
move_to_open(&valves, &find_distances(&valves), MoveState { move_to_open(&valves, &find_distances(&valves), MoveState {
curr: start, current: start,
next: start,
time_left: limit + 1, time_left: limit + 1,
closed: &closed_valves(valves) closed: &closed_valves(valves)
}) }, &mut HashMap::new())
} }
fn solve1((map, data): &(HashMap<&str, usize>, Vec<Valve>)) -> u32 { fn solve1((map, data): &(HashMap<&str, usize>, Vec<Valve>)) -> u32 {