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|
#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
#[derive(Debug)]
pub struct Map {
names: Vec<String>,
connectivity: Vec<Vec<usize>>,
paths: Vec<Vec<u64>>,
flow: Vec<u16>,
pos: usize,
elephant: usize,
}
impl advent_of_code::graph::Graph<usize, usize> for Map {
type Edges = Vec<usize>;
fn edges(&self, v: usize) -> Self::Edges {
self.connectivity[v].clone()
}
fn edge(&self, v: usize, e: usize) -> (usize, u64) {
(e, 1)
}
}
impl Map {
fn len(&self) -> usize {
self.flow.len()
}
fn room(&self, elephant: bool) -> &str {
&self.names[self.pos(elephant)]
}
fn can_stay(&self, elephant: bool) -> bool {
self.flow[self.pos(elephant)] > 0
}
fn done(&self) -> bool {
self.flow.iter().copied().all(|f| f == 0)
}
fn pos(&self, elephant: bool) -> usize {
if elephant {
self.elephant
} else {
self.pos
}
}
fn set_pos(&mut self, elephant: bool, pos: usize) {
if elephant {
self.elephant = pos;
} else {
self.pos = pos;
}
}
fn flow(&self, elephant: bool) -> u16 {
self.flow[self.pos(elephant)]
}
fn set_flow(&mut self, elephant: bool, flow: u16) {
let pos = self.pos(elephant);
self.flow[pos] = flow;
}
fn neighbors(&self, elephant: bool) -> &[usize] {
&self.connectivity[self.pos(elephant)]
}
}
pub fn parse(fh: File) -> Result<Map> {
let mut room_names = HashMap::new();
let mut connectivity = vec![];
let mut flow = vec![];
let room_idx = |s,
room_names: &mut HashMap<_, _>,
connectivity: &mut Vec<_>,
flow: &mut Vec<_>| {
*room_names.entry(s).or_insert_with(|| {
connectivity.push(vec![]);
flow.push(0);
flow.len() - 1
})
};
let mut pos = None;
for line in parse::raw_lines(fh) {
let cap = regex_captures!(
r"Valve ([^ ]+) has flow rate=(\d+); tunnels? leads? to valves? (.*)",
&line
)
.ok_or_else(|| anyhow!("failed to parse"))?;
let node_name = cap[1].to_string();
let node = room_idx(
node_name.clone(),
&mut room_names,
&mut connectivity,
&mut flow,
);
if node_name == "AA" {
pos = Some(node);
}
flow[node] = cap[2].parse()?;
connectivity[node] = cap[3]
.split(", ")
.map(|s| {
room_idx(
s.to_string(),
&mut room_names,
&mut connectivity,
&mut flow,
)
})
.collect();
}
let mut names = vec![];
names.resize_with(flow.len(), Default::default);
for (name, idx) in room_names {
names[idx] = name;
}
let mut map = Map {
names,
connectivity,
paths: vec![],
flow,
pos: pos.unwrap(),
elephant: pos.unwrap(),
};
for i in 0..map.connectivity.len() {
let mut paths = vec![0; map.connectivity.len()];
let prevs = map.dijkstra_full(i);
for (from, (_, distance)) in map.dijkstra_full(i) {
paths[from] = distance;
}
map.paths.push(paths);
}
Ok(map)
}
pub fn part1(mut map: Map) -> Result<u64> {
fn step(map: &mut Map, total: u64, time: u16) -> u64 {
if time >= 30 || map.done() {
return total;
}
let mut max = 0;
if map.can_stay(false) {
let stay_value = map.flow(false) as u64 * (29 - time as u64);
let flow = map.flow(false);
map.set_flow(false, 0);
let value = step(map, total + stay_value, time + 1);
if value > max {
max = value;
}
map.set_flow(false, flow);
} else {
let pos = map.pos(false);
for idx in 0..map.len() {
if idx == pos || map.flow[idx] == 0 {
continue;
}
let distance = map.paths[pos][idx];
map.set_pos(false, idx);
let value = step(map, total, time + distance as u16);
if value > max {
max = value;
}
map.set_pos(false, pos);
}
}
max
}
Ok(step(&mut map, 0, 0))
}
pub fn part2(mut map: Map) -> Result<u64> {
fn step(
map: &mut Map,
elephant: bool,
total: u64,
time: u16,
transit: u64,
elephant_transit: u64,
) -> u64 {
if time >= 26 || map.done() {
return total;
}
if elephant {
let elephant_transit = elephant_transit.saturating_sub(1);
if elephant_transit > 0 {
return step(
map,
!elephant,
total,
if elephant { time + 1 } else { time },
transit,
elephant_transit,
);
}
} else {
let transit = transit.saturating_sub(1);
if transit > 0 {
return step(
map,
!elephant,
total,
if elephant { time + 1 } else { time },
transit,
elephant_transit,
);
}
}
let mut max = 0;
if map.can_stay(elephant) {
let stay_value = map.flow(elephant) as u64 * (25 - time as u64);
let flow = map.flow(elephant);
map.set_flow(elephant, 0);
let value = step(
map,
!elephant,
total + stay_value,
if elephant { time + 1 } else { time },
transit,
elephant_transit,
);
if value > max {
max = value;
}
map.set_flow(elephant, flow);
} else {
let pos = map.pos(elephant);
for idx in 0..map.len() {
if idx == pos || map.flow[idx] == 0 {
continue;
}
let distance = map.paths[pos][idx];
map.set_pos(elephant, idx);
let value = step(
map,
!elephant,
total,
if elephant { time + 1 } else { time },
if elephant { transit } else { distance },
if elephant { distance } else { elephant_transit },
);
if value > max {
max = value;
}
map.set_pos(elephant, pos);
}
}
max
}
Ok(step(&mut map, false, 0, 0, 0, 0))
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2022, 16).unwrap()).unwrap()).unwrap(),
2359
);
// this one takes like 15 minutes to run/:
if false {
assert_eq!(
part2(parse(parse::data(2022, 16).unwrap()).unwrap()).unwrap(),
2999
);
}
}
|
