[rs] Solve 2022_16 part 1

inputs/2022/2022_16.input

@@ -0,0 +1,51 @@
+Valve NV has flow rate=5; tunnels lead to valves ZV, CG, YB, HX, OY
+Valve NU has flow rate=6; tunnels lead to valves DA, MA, OA, DK
+Valve VU has flow rate=0; tunnels lead to valves PS, FX
+Valve JW has flow rate=0; tunnels lead to valves AA, MD
+Valve RI has flow rate=0; tunnels lead to valves OY, DG
+Valve DG has flow rate=9; tunnels lead to valves TG, RI, DF, EV, KW
+Valve PH has flow rate=7; tunnels lead to valves KW, OW, LT, LZ
+Valve KZ has flow rate=12; tunnels lead to valves ET, QV, CK, MS
+Valve IX has flow rate=0; tunnels lead to valves TS, DO
+Valve MS has flow rate=0; tunnels lead to valves LZ, KZ
+Valve IL has flow rate=0; tunnels lead to valves DO, ET
+Valve EJ has flow rate=20; tunnels lead to valves AV, JY
+Valve DK has flow rate=0; tunnels lead to valves NU, CG
+Valve YB has flow rate=0; tunnels lead to valves NV, PS
+Valve OA has flow rate=0; tunnels lead to valves YA, NU
+Valve DA has flow rate=0; tunnels lead to valves NU, RG
+Valve KO has flow rate=0; tunnels lead to valves AA, TG
+Valve RG has flow rate=4; tunnels lead to valves DF, DA, ZV, MD, LB
+Valve MA has flow rate=0; tunnels lead to valves AA, NU
+Valve OW has flow rate=0; tunnels lead to valves DO, PH
+Valve KW has flow rate=0; tunnels lead to valves DG, PH
+Valve DO has flow rate=14; tunnels lead to valves IX, IL, CZ, OW
+Valve DF has flow rate=0; tunnels lead to valves RG, DG
+Valve TG has flow rate=0; tunnels lead to valves DG, KO
+Valve LB has flow rate=0; tunnels lead to valves RG, FX
+Valve HX has flow rate=0; tunnels lead to valves AA, NV
+Valve GB has flow rate=0; tunnels lead to valves AV, XK
+Valve CG has flow rate=0; tunnels lead to valves DK, NV
+Valve LT has flow rate=0; tunnels lead to valves AO, PH
+Valve FX has flow rate=23; tunnels lead to valves LB, HY, VU
+Valve ET has flow rate=0; tunnels lead to valves IL, KZ
+Valve CK has flow rate=0; tunnels lead to valves UX, KZ
+Valve LZ has flow rate=0; tunnels lead to valves PH, MS
+Valve YA has flow rate=17; tunnels lead to valves JY, OA
+Valve TS has flow rate=0; tunnels lead to valves NO, IX
+Valve NO has flow rate=8; tunnel leads to valve TS
+Valve XK has flow rate=24; tunnel leads to valve GB
+Valve PS has flow rate=18; tunnels lead to valves EV, VU, YB
+Valve AA has flow rate=0; tunnels lead to valves JW, HX, MA, KO
+Valve MD has flow rate=0; tunnels lead to valves JW, RG
+Valve JM has flow rate=19; tunnels lead to valves QV, HY, AO
+Valve AV has flow rate=0; tunnels lead to valves EJ, GB
+Valve AO has flow rate=0; tunnels lead to valves JM, LT
+Valve JY has flow rate=0; tunnels lead to valves YA, EJ
+Valve OY has flow rate=0; tunnels lead to valves NV, RI
+Valve UX has flow rate=13; tunnels lead to valves CZ, CK
+Valve HY has flow rate=0; tunnels lead to valves JM, FX
+Valve EV has flow rate=0; tunnels lead to valves PS, DG
+Valve CZ has flow rate=0; tunnels lead to valves UX, DO
+Valve ZV has flow rate=0; tunnels lead to valves NV, RG
+Valve QV has flow rate=0; tunnels lead to valves JM, KZ

inputs/2022/2022_16.solution

@@ -0,0 +1,2 @@
+Part 1: 1923
+Part 2: ???

rs/src/main.rs

@@ -66,6 +66,7 @@ days! {
     Y2022D13: "2022_13" => y2022::d13::solve,
     Y2022D14: "2022_14" => y2022::d14::solve,
     Y2022D15: "2022_15" => y2022::d15::solve,
+    Y2022D16: "2022_16" => y2022::d16::solve,
 }
 
 #[derive(Parser)]

rs/src/y2022.rs

@@ -13,3 +13,4 @@ pub mod d12;
 pub mod d13;
 pub mod d14;
 pub mod d15;
+pub mod d16;

rs/src/y2022/d16.rs

@@ -0,0 +1,127 @@
+use std::collections::HashMap;
+
+fn parse_valve(line: &str) -> (&str, u32, Vec<&str>) {
+    let (name, rest) = line
+        .strip_prefix("Valve ")
+        .unwrap()
+        .split_once(" has flow rate=")
+        .unwrap();
+    let (rate, rest) = rest.split_once("; ").unwrap();
+    let next = rest
+        .strip_prefix("tunnel leads to valve ")
+        .or_else(|| rest.strip_prefix("tunnels lead to valves "))
+        .unwrap()
+        .split(", ")
+        .collect::<Vec<_>>();
+    (name, rate.parse().unwrap(), next)
+}
+#[derive(Debug)]
+struct Valve {
+    rate: u32,
+    next: Vec<usize>,
+}
+
+fn prepare_valves<'a>(
+    mut valves: Vec<(&'a str, u32, Vec<&str>)>,
+) -> (HashMap<&'a str, usize>, Vec<Valve>) {
+    // All valves with a nonzero rate should come before the ones with a rate of
+    // zero. This will help with our valve bitset later.
+    valves.sort_by_key(|(_, rate, _)| *rate);
+    valves.reverse();
+
+    let names = valves
+        .iter()
+        .enumerate()
+        .map(|(i, (n, _, _))| (*n, i))
+        .collect::<HashMap<_, _>>();
+
+    let valves = valves
+        .into_iter()
+        .map(|(_, rate, next)| {
+            let next = next.into_iter().map(|n| names[n]).collect();
+            Valve { rate, next }
+        })
+        .collect::<Vec<_>>();
+
+    (names, valves)
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+struct OpenSet(u64);
+
+impl OpenSet {
+    const ALL_CLOSED: Self = Self(0);
+
+    /// The powerset of the set of all open valves.
+    fn powerset(valves: &[Valve]) -> Vec<Self> {
+        assert!(valves.len() <= 63);
+        let first_zero_rate = valves
+            .iter()
+            .position(|v| v.rate == 0)
+            .unwrap_or(valves.len());
+        let until = 2_u64.pow(first_zero_rate as u32);
+        (0..until).map(Self).collect::<Vec<_>>()
+    }
+
+    fn is_open(&self, valve_id: usize) -> bool {
+        assert!(valve_id < 63);
+        self.0 & (1 << valve_id) != 0
+    }
+
+    fn open(&self, valve_id: usize) -> Self {
+        assert!(valve_id < 63);
+        Self(self.0 | (1 << valve_id))
+    }
+}
+
+pub fn solve(input: String) {
+    let valves = input.lines().map(parse_valve).collect::<Vec<_>>();
+
+    let (names, valves) = prepare_valves(valves);
+    let powerset = OpenSet::powerset(&valves);
+    eprintln!("Powerset has size {}", powerset.len());
+
+    // DP state consists of:
+    // - The current minute
+    // - The current valve
+    // - The current set of open/closed valves
+
+    let mut dp = HashMap::new();
+
+    // Initialize for end state
+    eprintln!("Minute 0");
+    for valve_id in 0..valves.len() {
+        for open in &powerset {
+            dp.insert((0_u32, valve_id, *open), 0);
+        }
+    }
+
+    // Given valve v in minute t with set s, you can either...
+    // - Go to another neighbouring valve v', points: points[v', t-1, s]
+    // - If v not in s: Open current valve, points: points[v, t-1, s+{v}] + t
+
+    for minute in 1..=30 {
+        eprintln!("Minute {minute}");
+        for (valve_id, valve) in valves.iter().enumerate() {
+            for open in &powerset {
+                let mut score = valve
+                    .next
+                    .iter()
+                    .map(|next_id| dp[&(minute - 1, *next_id, *open)])
+                    .max()
+                    .unwrap_or(0);
+
+                if valve.rate > 0 && !open.is_open(valve_id) {
+                    let room_but_valve_open = dp[&(minute - 1, valve_id, open.open(valve_id))];
+                    let pressure_until_end = (minute - 1) * valve.rate;
+                    score = score.max(room_but_valve_open + pressure_until_end);
+                }
+
+                dp.insert((minute, valve_id, *open), score);
+            }
+        }
+    }
+
+    let part1 = dp[&(30, names["AA"], OpenSet::ALL_CLOSED)];
+    println!("Part 1: {part1}");
+}

sample_inputs/2022/2022_16.input

@@ -0,0 +1,10 @@
+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

sample_inputs/2022/2022_16.solution

@@ -0,0 +1,2 @@
+Part 1: 1651
+Part 2: ???