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Touches on 2022/day19-part1

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Tobias Marschner 2024-04-10 09:56:02 +02:00
parent 0e1053ec5e
commit aadb672532
1 changed files with 6 additions and 7 deletions
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13
2022/day19-part1/src/main.rs
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@ -13,6 +13,8 @@ struct Blueprint {
optimal_geode_count: u16, optimal_geode_count: u16,
} }
const TOTAL_RUNTIME: usize = 24;
impl Blueprint { impl Blueprint {
// Solve the given blueprint using BFS. // Solve the given blueprint using BFS.
fn solve_bfs(&mut self) { fn solve_bfs(&mut self) {
@ -37,7 +39,7 @@ impl Blueprint {
// Iterate over all timeslots. // Iterate over all timeslots.
// Building a robot at t=1 cannot influence the final geode-count, // Building a robot at t=1 cannot influence the final geode-count,
// so it's omitted from the simulation here. // so it's omitted from the simulation here.
for ts in (2usize..=24).rev() { for ts in (2usize..=TOTAL_RUNTIME).rev() {
// println!("Now at {} remaining time. Processing {} input RSs ...", ts, next_hs.len()); // println!("Now at {} remaining time. Processing {} input RSs ...", ts, next_hs.len());
// Process every RS of the past timeslot // Process every RS of the past timeslot
@ -163,7 +165,7 @@ impl RecursionState {
// Copy over states for the next simulation round, pruning a lot of (but not all) // Copy over states for the next simulation round, pruning a lot of (but not all)
// RecursionStates that are "strictly inferior" in terms of Pareto optimality. // RecursionStates that are "strictly inferior" in terms of Pareto optimality.
// Will clear any previously present elements in dest. // Will clear any previously present elements in `dest`.
// //
// A few words on the general idea here: // A few words on the general idea here:
// The goal here is to check for Pareto improvements. An example: // The goal here is to check for Pareto improvements. An example:
@ -182,9 +184,6 @@ fn prune_states(source: &mut [RecursionState], dest: &mut Vec<RecursionState>) {
// Begin by sorting the source lexicrgraphically and clearing the destination. // Begin by sorting the source lexicrgraphically and clearing the destination.
source.sort_unstable(); source.sort_unstable();
dest.clear(); dest.clear();
// Add one more element to the source, at the very end,
// that is a copy of the last element +1 ore.
// This is to ensure that the actual last element
// Iterate through it from smallest to largest element and look at every pair of states. // Iterate through it from smallest to largest element and look at every pair of states.
for (a, b) in source.iter().zip(source.iter().skip(1)) { for (a, b) in source.iter().zip(source.iter().skip(1)) {
// Don't copy a over if it is strictly inferior or equal to b. // Don't copy a over if it is strictly inferior or equal to b.
@ -201,7 +200,7 @@ fn prune_states(source: &mut [RecursionState], dest: &mut Vec<RecursionState>) {
dest.push(*a); dest.push(*a);
} }
} }
// Copy over the very last element, guaranteed to be part of the frontier. // Copy over the very last element, too.
dest.push(*source.last().unwrap()); dest.push(*source.last().unwrap());
} }
@ -235,7 +234,7 @@ fn main() {
// Solve for every blueprint. // Solve for every blueprint.
for bp in &mut blueprints { for bp in &mut blueprints {
// Solve every blueprint with 24 minutes of time. // Solve every blueprint with TOTAL_RUNTIME minutes of time.
println!("Solving Blueprint {}", bp.id); println!("Solving Blueprint {}", bp.id);
bp.solve_bfs(); bp.solve_bfs();
} }