day16 pt2

2 files changed, 93 insertions, 50 deletions

diff --git a/src/day16.rs b/src/day16.rs
index da1709c..03e7945 100644
--- a/src/day16.rs
+++ b/src/day16.rs
@@ -4,7 +4,8 @@ use regex::Regex;
 
 #[derive(Debug,Clone)]
 struct Track {
-    current_valve: String,
+    my_current_valve: String,
+    elephant_current_valve: String,
     final_pressure_release: u32,
     valves_opened: Vec<String>,
     debug: String,
@@ -14,6 +15,24 @@ struct Valve {
     flow_rate: u32,
     next_valves: Vec<String>,
 }
+
+#[derive(PartialEq)]
+enum Move {Open, Move(String)}
+
+fn poss_moves(valves: &HashMap<String,Valve>, current_valve: &String, open_valves: &Vec<String>) -> Vec<Move> {
+    let mut res = vec![];
+    let cv = &valves[current_valve];
+    // try open the valve (if it's got any flow, and if it's not already open)
+    if cv.flow_rate > 0 && !open_valves.contains(current_valve) {
+        res.push(Move::Open);
+    }
+    // Alt, try moving to another valve
+    for nv in &cv.next_valves {
+        res.push(Move::Move(nv.clone()));
+    }
+    res
+}
+
 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| {
@@ -29,34 +48,58 @@ pub fn run(input: String) {
     // 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 root = Track {my_current_valve: "AA".to_string(), elephant_current_valve: "AA".to_string(), final_pressure_release:0, valves_opened: vec![], debug: "Start at AA\n".to_string()};
     let mut tracks: Vec<Track> = vec![root];
     let mut next_tracks: Vec<Track> = Vec::new();
-    let total_mins: u32 = 30;
+    //let total_mins: u32 = 30;
+    let total_mins: u32 = 26;
     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);
+            // Cartesian the next moves by me and the elephant
+            // For each in the product, calculate changed final_pressure_release (if we opened a valve(s))
+            // And extend the debug string!
+            let my_poss_moves = poss_moves(&valves, &track.my_current_valve, &track.valves_opened);
+            for mm in my_poss_moves {
+                let mut vo = track.valves_opened.clone();
+                if mm == Move::Open {
+                    vo.push(track.my_current_valve.clone()); // Care, we don't try to open the same valve at once.
+                }
+                let e_poss_moves = poss_moves(&valves, &track.elephant_current_valve, &vo);
+                for em in e_poss_moves {
+                    let mut nt = track.clone();
+                    nt.debug.push_str(format!("minute {}", minute+1).as_str());
+                    if let Move::Move(nv) = &mm {
+                        nt.my_current_valve = nv.clone();
+                        nt.debug.push_str(format!(", I Moved To {}", nv).as_str());
+                    } else {
+                        nt.valves_opened.push(track.my_current_valve.clone());
+                        let cv = &valves[&track.my_current_valve];
+                        if mins_remaining > 0 {
+                            nt.final_pressure_release += cv.flow_rate * (mins_remaining-1);
+                        }
+                        nt.debug.push_str(format!(", I Opened {}", track.my_current_valve).as_str());
+                    } 
+                    if let Move::Move(nv) = &em {
+                        nt.elephant_current_valve = nv.clone();
+                        nt.debug.push_str(format!(", Elephant Moved To {}", nv).as_str());
+                    } else {
+                        nt.valves_opened.push(track.elephant_current_valve.clone());
+                        let cv = &valves[&track.elephant_current_valve];
+                        if mins_remaining > 0 {
+                            nt.final_pressure_release += cv.flow_rate * (mins_remaining-1);
+                        }
+                        nt.debug.push_str(format!(", Elephant Opened {}", track.elephant_current_valve).as_str());  
+                    }
+                    nt.debug.push('\n');
+                    next_tracks.push(nt);
                 }
-                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));
+        // 3.pow(30) is too many options, just prune weak ones.
+        // It means we can only make maybe a couple of non-optimal steps, so we might get stuck in a local maximum.
+        next_tracks.truncate(3_usize.pow(8));
         tracks = next_tracks.clone();
         next_tracks = Vec::new();// prune? keep the top N scorers?
     }
diff --git a/src/main.rs b/src/main.rs
index afee780..bdbb41e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,38 +2,38 @@
 #![feature(iterator_try_collect)]
 use std::fs;
 
-mod day1;
-mod day2;
-mod day3;
-mod day4;
-mod day5;
-mod day6;
-mod day7;
-mod day8;
-mod day9;
-mod day10;
-mod day11;
-mod day12;
-mod day13;
-mod day14;
-mod day15;
+// mod day1;
+// mod day2;
+// mod day3;
+// mod day4;
+// mod day5;
+// mod day6;
+// mod day7;
+// mod day8;
+// mod day9;
+// mod day10;
+// mod day11;
+// mod day12;
+// mod day13;
+// mod day14;
+// mod day15;
 mod day16;
 
 fn main() {
-    day1::run(fs::read_to_string("input/day1.txt").expect("Failed to read input file!"));
-    day2::run(fs::read_to_string("input/day2.txt").expect("Failed to read input file!"));
-    day3::run(fs::read_to_string("input/day3.txt").expect("Failed to read input file!"));
-    day4::run(fs::read_to_string("input/day4.txt").expect("Failed to read input file!"));
-    day5::run(fs::read_to_string("input/day5.txt").expect("Failed to read input file!"));
-    day6::run(fs::read_to_string("input/day6.txt").expect("Failed to read input file!"));
-    day7::run(fs::read_to_string("input/day7.txt").expect("Failed to read input file!"));
-    day8::run(fs::read_to_string("input/day8.txt").expect("Failed to read input file!"));
-    day9::run(fs::read_to_string("input/day9.txt").expect("Failed to read input file!"));
-    day10::run(fs::read_to_string("input/day10.txt").expect("Failed to read input file!"));
-    day11::run(fs::read_to_string("input/day11.txt").expect("Failed to read input file!"));
-    day12::run(fs::read_to_string("input/day12.txt").expect("Failed to read input file!"));
-    day13::run(fs::read_to_string("input/day13.txt").expect("Failed to read input file!"));
-    day14::run(fs::read_to_string("input/day14.txt").expect("Failed to read input file!"));
-    day15::run(fs::read_to_string("input/day15.txt").expect("Failed to read input file!"));
+    // day1::run(fs::read_to_string("input/day1.txt").expect("Failed to read input file!"));
+    // day2::run(fs::read_to_string("input/day2.txt").expect("Failed to read input file!"));
+    // day3::run(fs::read_to_string("input/day3.txt").expect("Failed to read input file!"));
+    // day4::run(fs::read_to_string("input/day4.txt").expect("Failed to read input file!"));
+    // day5::run(fs::read_to_string("input/day5.txt").expect("Failed to read input file!"));
+    // day6::run(fs::read_to_string("input/day6.txt").expect("Failed to read input file!"));
+    // day7::run(fs::read_to_string("input/day7.txt").expect("Failed to read input file!"));
+    // day8::run(fs::read_to_string("input/day8.txt").expect("Failed to read input file!"));
+    // day9::run(fs::read_to_string("input/day9.txt").expect("Failed to read input file!"));
+    // day10::run(fs::read_to_string("input/day10.txt").expect("Failed to read input file!"));
+    // day11::run(fs::read_to_string("input/day11.txt").expect("Failed to read input file!"));
+    // day12::run(fs::read_to_string("input/day12.txt").expect("Failed to read input file!"));
+    // day13::run(fs::read_to_string("input/day13.txt").expect("Failed to read input file!"));
+    // day14::run(fs::read_to_string("input/day14.txt").expect("Failed to read input file!"));
+    // day15::run(fs::read_to_string("input/day15.txt").expect("Failed to read input file!"));
     day16::run(fs::read_to_string("input/day16.txt").expect("Failed to read input file!"));
 }