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Diffstat (limited to 'src/day16.rs')
| -rw-r--r-- | src/day16.rs | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/src/day16.rs b/src/day16.rs new file mode 100644 index 0000000..da1709c --- /dev/null +++ b/src/day16.rs @@ -0,0 +1,67 @@ +use std::collections::HashMap; + +use regex::Regex; + +#[derive(Debug,Clone)] +struct Track { + current_valve: String, + final_pressure_release: u32, + valves_opened: Vec<String>, + debug: String, +} +#[derive(Debug)] +struct Valve { + flow_rate: u32, + next_valves: Vec<String>, +} +pub fn run(input: String) { + let re = Regex::new(r"^Valve ([A-Z]+) has flow rate=(\d+); tunnels? leads? to valves? ([A-Z, ]+)$").unwrap(); + let valves: HashMap<String,Valve> = input.lines().map(|line| { + let cap = re.captures(line).expect(format!("line didn't match regex! {}", line).as_str()); + let name = cap[1].to_string(); + let flow_rate: u32 = cap[2].parse().expect("flow rate wasn't a u32!"); + let next_valves: Vec<String> = cap[3].split(", ").map(|x| { x.to_string() }).collect(); + (name, Valve{flow_rate,next_valves}) + }).collect(); + // How to do this one? + // I think... tracking all options? It's basically a tree right? + // max depth of the tree is 30,corresponding to minutes + // at each depth, options are -> open valve OR move to another valve + // and at each depth we have a score, and a list of already-opened valves + + let root = Track {current_valve: "AA".to_string(), final_pressure_release:0, valves_opened: vec![], debug: "Start at AA".to_string()}; + let mut tracks: Vec<Track> = vec![root]; + let mut next_tracks: Vec<Track> = Vec::new(); + let total_mins: u32 = 30; + for minute in 0..=total_mins { + let mins_remaining = total_mins - minute; + for track in &tracks { + let cv = &valves[&track.current_valve]; + // try open the valve (if it's got any flow, and if it's not already open) + if cv.flow_rate > 0 && !track.valves_opened.contains(&track.current_valve) { + let mut nt = track.clone(); + nt.valves_opened.push(track.current_valve.clone()); + if mins_remaining > 0 { + nt.final_pressure_release += cv.flow_rate * (mins_remaining-1); + } + nt.debug.push_str(format!(", Opened {}", track.current_valve).as_str()); + next_tracks.push(nt); + } + // Alt, try moving to another valve + for nv in &cv.next_valves { + let mut nt = track.clone(); + nt.current_valve = nv.clone(); + nt.debug.push_str(format!(", Moved to {}", nv).as_str()); + next_tracks.push(nt); + } + } + next_tracks.sort_by(|t1, t2| {t1.final_pressure_release.cmp(&t2.final_pressure_release)}.reverse()); + next_tracks.truncate(3_usize.pow(5)); + tracks = next_tracks.clone(); + next_tracks = Vec::new();// prune? keep the top N scorers? + } + // Find the track with the biggest final score + let max_track = tracks.iter().max_by(|t1,t2| {t1.final_pressure_release.cmp(&t2.final_pressure_release)}).unwrap(); + //let max_pressure_release = tracks.iter().map(|t| {t.final_pressure_release}).max().unwrap(); + println!("Day 16: {}", max_track.final_pressure_release); +}
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