Rust/2024/24: add solution

Author: Defelo

README.md

@@ -0,0 +1,153 @@
+#![feature(test)]
+#![expect(unstable_name_collisions)]
+
+use itertools::Itertools;
+use rustc_hash::{FxHashMap, FxHashSet};
+
+#[derive(Debug)]
+struct Input {
+    values: FxHashMap<String, bool>,
+    gates: FxHashMap<String, (Gate, String, String)>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Gate {
+    And,
+    Or,
+    Xor,
+}
+
+fn setup(input: &str) -> Input {
+    let mut lines = input.lines();
+    let values = lines
+        .by_ref()
+        .take_while(|l| !l.trim().is_empty())
+        .map(|l| {
+            let mut s = l.split(": ");
+            let name = s.next().unwrap().into();
+            let value = s.next().unwrap().trim() == "1";
+            (name, value)
+        })
+        .collect();
+
+    let gates = lines
+        .map(|l| {
+            let mut s = l.split_whitespace();
+            let a = s.next().unwrap().into();
+            let gate = match s.next().unwrap() {
+                "AND" => Gate::And,
+                "OR" => Gate::Or,
+                "XOR" => Gate::Xor,
+                _ => panic!(),
+            };
+            let b = s.next().unwrap().into();
+            s.next();
+            let c = s.next().unwrap().into();
+            (c, (gate, a, b))
+        })
+        .collect();
+
+    Input { values, gates }
+}
+
+fn part1(input: &Input) -> usize {
+    let mut forward = FxHashMap::<_, Vec<_>>::default();
+    let mut unknown = input
+        .gates
+        .iter()
+        .map(|(c, (_, a, b))| {
+            forward.entry(a).or_default().push(c);
+            forward.entry(b).or_default().push(c);
+            let dependencies = [a, b]
+                .into_iter()
+                .filter(|&x| !input.values.contains_key(x))
+                .collect::<FxHashSet<_>>();
+            (c, dependencies)
+        })
+        .filter(|(_, v)| !v.is_empty())
+        .collect::<FxHashMap<_, _>>();
+    let mut values = input
+        .values
+        .iter()
+        .map(|(p, &v)| (p, v))
+        .collect::<FxHashMap<_, _>>();
+    let mut stack = input
+        .gates
+        .keys()
+        .filter(|&p| !unknown.contains_key(p))
+        .collect::<Vec<_>>();
+    while let Some(p) = stack.pop() {
+        let (gate, ref a, ref b) = input.gates[p];
+        let a = values[a];
+        let b = values[b];
+        let c = match gate {
+            Gate::And => a & b,
+            Gate::Or => a | b,
+            Gate::Xor => a ^ b,
+        };
+        values.insert(p, c);
+
+        for &q in forward.get(p).into_iter().flatten() {
+            if unknown.contains_key(q) {
+                unknown.get_mut(q).unwrap().remove(p);
+                if unknown[q].is_empty() {
+                    unknown.remove(q);
+                    stack.push(q);
+                }
+            }
+        }
+    }
+
+    values
+        .keys()
+        .filter(|k| k.starts_with('z'))
+        .sorted_unstable()
+        .rev()
+        .fold(0, |acc, k| acc << 1 | (values[k] as usize))
+}
+
+fn part2(input: &Input) -> String {
+    let last_z = input
+        .gates
+        .keys()
+        .filter(|k| k.starts_with('z'))
+        .max()
+        .unwrap();
+    let mut forward = FxHashMap::<_, Vec<_>>::default();
+    for (c, (_, a, b)) in &input.gates {
+        forward.entry(a).or_default().push(c);
+        forward.entry(b).or_default().push(c);
+    }
+    input
+        .gates
+        .keys()
+        .filter(|&g| {
+            let (gate, ref a, ref b) = input.gates[g];
+            gate != Gate::Xor && g.starts_with('z') && g != last_z
+                || gate == Gate::Xor
+                    && forward
+                        .get(g)
+                        .into_iter()
+                        .flatten()
+                        .any(|&x| input.gates[x].0 == Gate::Or)
+                || gate == Gate::And
+                    && a != "x00"
+                    && b != "x00"
+                    && forward
+                        .get(g)
+                        .into_iter()
+                        .flatten()
+                        .any(|&x| input.gates[x].0 != Gate::Or)
+                || gate == Gate::Xor
+                    && !g.starts_with('z')
+                    && [a, b]
+                        .into_iter()
+                        .any(|x| input.gates.get(x).is_some_and(|x| x.0 == Gate::Xor))
+        })
+        .sorted_unstable()
+        .map(|s| s.as_str())
+        .intersperse(",")
+        .collect()
+}
+
+aoc::main!(2024, 24, ex: 1[a], 2[a]);

Rust/2024/24.rs

@@ -22,6 +22,6 @@ aoc::year! {
     "21.rs",
     "22.rs",
     "23.rs",
-    // "24.rs",
+    "24.rs",
     "25.rs",
 }

Rust/2024/main.rs

@@ -430,5 +430,8 @@ path = "2024/22.rs"
 name = "2024_23"
 path = "2024/23.rs"
 [[bin]]
+name = "2024_24"
+path = "2024/24.rs"
+[[bin]]
 name = "2024_25"
 path = "2024/25.rs"

Rust/Cargo.toml

@@ -0,0 +1,10 @@
+x00: 1
+x01: 1
+x02: 1
+y00: 0
+y01: 1
+y02: 0
+
+x00 AND y00 -> z00
+x01 XOR y01 -> z01
+x02 OR y02 -> z02

examples/2024/24/1

@@ -0,0 +1 @@
+4

examples/2024/24/1.1

@@ -0,0 +1,47 @@
+x00: 1
+x01: 0
+x02: 1
+x03: 1
+x04: 0
+y00: 1
+y01: 1
+y02: 1
+y03: 1
+y04: 1
+
+ntg XOR fgs -> mjb
+y02 OR x01 -> tnw
+kwq OR kpj -> z05
+x00 OR x03 -> fst
+tgd XOR rvg -> z01
+vdt OR tnw -> bfw
+bfw AND frj -> z10
+ffh OR nrd -> bqk
+y00 AND y03 -> djm
+y03 OR y00 -> psh
+bqk OR frj -> z08
+tnw OR fst -> frj
+gnj AND tgd -> z11
+bfw XOR mjb -> z00
+x03 OR x00 -> vdt
+gnj AND wpb -> z02
+x04 AND y00 -> kjc
+djm OR pbm -> qhw
+nrd AND vdt -> hwm
+kjc AND fst -> rvg
+y04 OR y02 -> fgs
+y01 AND x02 -> pbm
+ntg OR kjc -> kwq
+psh XOR fgs -> tgd
+qhw XOR tgd -> z09
+pbm OR djm -> kpj
+x03 XOR y03 -> ffh
+x00 XOR y04 -> ntg
+bfw OR bqk -> z06
+nrd XOR fgs -> wpb
+frj XOR qhw -> z04
+bqk OR frj -> z07
+y03 OR x01 -> nrd
+hwm AND bqk -> z03
+tgd XOR rvg -> z12
+tnw OR pbm -> gnj

examples/2024/24/2

@@ -0,0 +1 @@
+2024