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Non-functional implementation of 2022 day 16 part 1

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Bert Peters
2022-12-17 11:04:46 +01:00
parent 84110350ff
commit 9aad6fe511
3 changed files with 300 additions and 3 deletions
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50
2022/inputs/16.txt Normal file
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Valve QJ has flow rate=11; tunnels lead to valves HB, GL
Valve VZ has flow rate=10; tunnel leads to valve NE
Valve TX has flow rate=19; tunnels lead to valves MG, OQ, HM
Valve ZI has flow rate=5; tunnels lead to valves BY, ON, RU, LF, JR
Valve IH has flow rate=0; tunnels lead to valves YB, QS
Valve QS has flow rate=22; tunnel leads to valve IH
Valve QB has flow rate=0; tunnels lead to valves QX, ES
Valve NX has flow rate=0; tunnels lead to valves UH, OP
Valve PJ has flow rate=0; tunnels lead to valves OC, UH
Valve OR has flow rate=6; tunnels lead to valves QH, BH, HB, JD
Valve OC has flow rate=7; tunnels lead to valves IZ, JR, TA, ZH, PJ
Valve UC has flow rate=0; tunnels lead to valves AA, BY
Valve QX has flow rate=0; tunnels lead to valves AA, QB
Valve IZ has flow rate=0; tunnels lead to valves OC, SX
Valve AG has flow rate=13; tunnels lead to valves NW, GL, SM
Valve ON has flow rate=0; tunnels lead to valves MO, ZI
Valve XT has flow rate=18; tunnels lead to valves QZ, PG
Valve AX has flow rate=0; tunnels lead to valves UH, MO
Valve JD has flow rate=0; tunnels lead to valves OR, SM
Valve HM has flow rate=0; tunnels lead to valves TX, QH
Valve LF has flow rate=0; tunnels lead to valves ZI, UH
Valve QH has flow rate=0; tunnels lead to valves OR, HM
Valve RT has flow rate=21; tunnel leads to valve PG
Valve NE has flow rate=0; tunnels lead to valves VZ, TA
Valve OQ has flow rate=0; tunnels lead to valves TX, GE
Valve AA has flow rate=0; tunnels lead to valves QZ, UC, OP, QX, EH
Valve UH has flow rate=17; tunnels lead to valves PJ, NX, AX, LF
Valve GE has flow rate=0; tunnels lead to valves YB, OQ
Valve EH has flow rate=0; tunnels lead to valves AA, MO
Valve MG has flow rate=0; tunnels lead to valves TX, NW
Valve YB has flow rate=20; tunnels lead to valves IH, GE, XG
Valve MO has flow rate=15; tunnels lead to valves EH, ON, AX, ZH, CB
Valve JR has flow rate=0; tunnels lead to valves ZI, OC
Valve GL has flow rate=0; tunnels lead to valves AG, QJ
Valve SM has flow rate=0; tunnels lead to valves JD, AG
Valve HB has flow rate=0; tunnels lead to valves OR, QJ
Valve TA has flow rate=0; tunnels lead to valves OC, NE
Valve PG has flow rate=0; tunnels lead to valves RT, XT
Valve XG has flow rate=0; tunnels lead to valves CB, YB
Valve ES has flow rate=9; tunnels lead to valves QB, FL
Valve BH has flow rate=0; tunnels lead to valves RU, OR
Valve FL has flow rate=0; tunnels lead to valves SX, ES
Valve CB has flow rate=0; tunnels lead to valves MO, XG
Valve QZ has flow rate=0; tunnels lead to valves AA, XT
Valve BY has flow rate=0; tunnels lead to valves UC, ZI
Valve ZH has flow rate=0; tunnels lead to valves MO, OC
Valve OP has flow rate=0; tunnels lead to valves NX, AA
Valve NW has flow rate=0; tunnels lead to valves MG, AG
Valve RU has flow rate=0; tunnels lead to valves ZI, BH
Valve SX has flow rate=16; tunnels lead to valves IZ, FL

243
2022/src/day16.rs
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use anyhow::Result;
use std::collections::VecDeque;
pub fn part1(_input: &[u8]) -> Result<String> {
anyhow::bail!("not implemented")
use ahash::AHashMap;
use ahash::AHashSet;
use anyhow::Result;
use nom::branch::alt;
use nom::bytes::complete::tag;
use nom::character::complete::alpha1;
use nom::character::complete::newline;
use nom::combinator::into;
use nom::multi::fold_many1;
use nom::multi::separated_list1;
use nom::sequence::preceded;
use nom::sequence::terminated;
use nom::sequence::tuple;
use nom::IResult;
use crate::common::parse_input;
type ParsedNetwork<'a> = AHashMap<&'a [u8], ParsedValve<'a>>;
struct ParsedValve<'a> {
connected: Vec<&'a [u8]>,
flow: u32,
}
#[derive(Debug)]
struct SimpleNetwork {
valves: Vec<SimpleValve>,
start: usize,
}
#[derive(Debug)]
struct SimpleValve {
connected: Vec<(usize, u8)>,
flow: u32,
}
impl From<ParsedNetwork<'_>> for SimpleNetwork {
fn from(parsed: ParsedNetwork) -> Self {
let mapping: AHashMap<_, _> = parsed
.iter()
.filter_map(|(&k, v)| (v.flow > 0 || k == b"AA").then_some(k))
.enumerate()
.map(|(i, v)| (v, i))
.collect();
let mut todo = VecDeque::new();
let mut seen = AHashSet::new();
let mut network = Vec::with_capacity(mapping.len());
for (&key, valve_data) in &parsed {
if valve_data.flow == 0 && key != b"AA" {
continue;
}
todo.extend(valve_data.connected.iter().map(|&valve| (valve, 1)));
let mut connected = Vec::new();
seen.clear();
while let Some((valve, dist)) = todo.pop_front() {
if seen.insert(valve) {
let data = &parsed[&valve];
if data.flow != 0 {
connected.push((mapping[valve], dist));
}
for &other in &data.connected {
if other != key {
todo.push_back((other, dist + 1));
}
}
}
}
network.push(SimpleValve {
flow: valve_data.flow,
connected,
})
}
Self {
valves: network,
start: mapping[&b"AA"[..]],
}
}
}
fn parse_network(input: &[u8]) -> IResult<&[u8], ParsedNetwork> {
let parse_network = terminated(
tuple((
// Parse the name of the valve
preceded(tag("Valve "), alpha1),
// Parse the flow of the valve
preceded(tag(" has flow rate="), nom::character::complete::u32),
// Parse the connections
preceded(
// Did you really have to distinguish plural
alt((
tag("; tunnels lead to valves "),
tag("; tunnel leads to valve "),
)),
separated_list1(tag(", "), alpha1),
),
)),
newline,
);
fold_many1(
parse_network,
ParsedNetwork::new,
|mut map, (valve, flow, connected)| {
map.insert(valve, ParsedValve { flow, connected });
map
},
)(input)
}
#[derive(Eq, PartialEq, Hash, Debug, Clone)]
struct State {
pos: usize,
valves_open: u32,
}
impl State {
fn open(&self) -> Option<State> {
let bit = 1 << self.pos;
if (self.valves_open & bit) == 0 {
Some(State {
pos: self.pos,
valves_open: self.valves_open | bit,
})
} else {
None
}
}
pub fn is_open(&self, pos: usize) -> bool {
(self.valves_open & (1 << pos)) != 0
}
}
impl Ord for State {
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
// Reversed because having fewer valves with the same score gives more opportunities for gains
self.valves_open
.count_ones()
.cmp(&other.valves_open.count_ones())
// Compare open valves and pos. Shouldn't really matter but required for a total order.
.then(self.valves_open.cmp(&other.valves_open))
.then(self.pos.cmp(&other.pos))
}
}
impl PartialOrd for State {
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
Some(self.cmp(other))
}
}
pub fn part1(input: &[u8]) -> Result<String> {
let network: SimpleNetwork = parse_input(input, into(parse_network))?;
let mut best = AHashMap::new();
let initial_state = State {
valves_open: 0,
pos: network.start,
};
best.insert(initial_state.clone(), 0);
let mut todo = VecDeque::new();
todo.push_back((0, 0, initial_state));
let mut best_score = 0;
while let Some((score, minute, state)) = todo.pop_front() {
if best[&state] > score {
continue;
}
let mut enqueue = |score, minute, state: State| {
if minute >= 29
|| best
.get(&state)
.map(|&previous| previous >= score)
.unwrap_or(false)
{
return;
}
best.insert(state.clone(), score);
todo.push_back((score, minute, state));
};
if let Some(new_state) = state.open() {
let pos = new_state.pos;
let valve_strength = network.valves[pos].flow;
let time_remaining = 29 - minute;
let new_score = score + time_remaining as u32 * network.valves[pos].flow;
println!("Opening valve {pos} for {valve_strength} for {time_remaining} minutes: {new_score} ({best_score})");
best_score = best_score.max(new_score);
enqueue(new_score, minute + 1, new_state)
}
for &(other, dist) in &network.valves[state.pos].connected {
if state.is_open(other) {
continue;
}
let new_state = State {
pos: other,
valves_open: state.valves_open,
};
enqueue(score, minute + dist, new_state);
}
}
// Guesses: 1802 (too low)
Ok(best_score.to_string())
}
pub fn part2(_input: &[u8]) -> Result<String> {
anyhow::bail!("not implemented")
}
#[cfg(test)]
mod tests {
use super::*;
const SAMPLE: &[u8] = include_bytes!("samples/16.txt");
#[test]
fn sample_part1() {
assert_eq!(part1(SAMPLE).unwrap(), "1651");
}
}

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Valve AA has flow rate=0; tunnels lead to valves DD, II, BB
Valve BB has flow rate=13; tunnels lead to valves CC, AA
Valve CC has flow rate=2; tunnels lead to valves DD, BB
Valve DD has flow rate=20; tunnels lead to valves CC, AA, EE
Valve EE has flow rate=3; tunnels lead to valves FF, DD
Valve FF has flow rate=0; tunnels lead to valves EE, GG
Valve GG has flow rate=0; tunnels lead to valves FF, HH
Valve HH has flow rate=22; tunnel leads to valve GG
Valve II has flow rate=0; tunnels lead to valves AA, JJ
Valve JJ has flow rate=21; tunnel leads to valve II