chore: y2025::day_07

Author: clechasseur

.run/run_aoc.run.xml

@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="run_aoc" type="CargoCommandRunConfiguration" factoryName="Cargo Command">
     <option name="buildProfileId" value="dev" />
-    <option name="command" value="run --package aoclp_solutions --bin aoclp_solutions -- --year 2024 --day 9" />
+    <option name="command" value="run --package aoclp_solutions --bin aoclp_solutions -- --year 2025 --day 7" />
     <option name="workingDirectory" value="file://$PROJECT_DIR$" />
     <envs />
     <option name="emulateTerminal" value="true" />

Cargo.lock

@@ -8,6 +8,7 @@ anyhow = "1.0.100"
 aocf = "0.1.21"
 bit-vec = "0.8.0"
 clap = { version = "4.5.53", features = ["derive"] }
+derive-where = "1.6.0"
 fancy-regex = "0.16.2"
 itertools = "0.14.0"
 num = "0.4.3"

Cargo.toml

@@ -8,7 +8,7 @@ rust-version = "1.81.0"
 aoclp = { path = "../aoclp" }
 bit-vec = { workspace = true }
 clap = { workspace = true, features = ["derive"] }
-fancy-regex = { workspace = true }
+derive-where = { workspace = true }
 itertools = { workspace = true }
 paste = { workspace = true }
 primes = { workspace = true }

aoclp_solutions/Cargo.toml

@@ -11,5 +11,5 @@ pub mod y2025;
 build_solvers! {
     { 2017, [01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25] },
     { 2024, [01, 02, 03, 04, 05, 06, 07, 08, 09] },
-    { 2025, [01, 02, 03, 04, 05, 06] }
+    { 2025, [01, 02, 03, 04, 05, 06, 07] }
 }

aoclp_solutions/src/lib.rs

@@ -0,0 +1,104 @@
+use std::collections::HashMap;
+
+use aoclp::positioning::direction::four_points::Direction4;
+use aoclp::positioning::pt::{matrix_to_map, Pt};
+use aoclp::solvers_impl::input::safe_get_input_as_terrain;
+use derive_where::derive_where;
+use itertools::Itertools;
+
+pub fn part_1() -> usize {
+    manifoldize().splits
+}
+
+pub fn part_2() -> usize {
+    manifoldize().worlds
+}
+
+#[derive(Debug, Clone)]
+struct Manifold {
+    parts: HashMap<Pt, char>,
+    starting_point: Pt,
+}
+
+impl Default for Manifold {
+    fn default() -> Self {
+        let parts = matrix_to_map(input());
+        let starting_point = *parts.iter().find(|(_, c)| **c == 'S').unwrap().0;
+        Self { parts, starting_point }
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+#[derive_where(PartialEq, Eq, PartialOrd, Ord, Hash)]
+struct Particle {
+    pos: Pt,
+    #[derive_where(skip)]
+    worlds: usize,
+}
+
+impl Particle {
+    fn initial(manifold: &Manifold) -> Self {
+        Self { pos: manifold.starting_point, worlds: 1 }
+    }
+
+    fn travel(self, dir: Direction4) -> Self {
+        Self { pos: self.pos + dir, ..self }
+    }
+
+    fn onward(self, manifold: &Manifold) -> Vec<Self> {
+        let next = self.travel(Direction4::Down);
+        if !manifold.parts.contains_key(&next.pos) {
+            return vec![self];
+        }
+
+        if manifold.parts.get(&next.pos).is_some_and(|c| *c == '^') {
+            vec![next.travel(Direction4::Left), next.travel(Direction4::Right)]
+        } else {
+            vec![next]
+        }
+    }
+}
+
+struct ManifoldizationResult {
+    splits: usize,
+    worlds: usize,
+}
+
+fn manifoldize() -> ManifoldizationResult {
+    let manifold = Manifold::default();
+    let mut particles = vec![Particle::initial(&manifold)];
+
+    let mut splits = 0;
+    loop {
+        let new_particles = particles
+            .iter()
+            .flat_map(|particle| {
+                let moved = particle.onward(&manifold);
+                if moved.len() > 1 {
+                    splits += 1;
+                }
+                moved
+            })
+            .sorted()
+            .coalesce(|a, b| {
+                if a == b {
+                    Ok(Particle { pos: a.pos, worlds: a.worlds + b.worlds })
+                } else {
+                    Err((a, b))
+                }
+            })
+            .collect_vec();
+
+        if new_particles == particles {
+            break;
+        }
+        particles = new_particles;
+    }
+
+    let worlds = particles.into_iter().map(|p| p.worlds).sum();
+    ManifoldizationResult { splits, worlds }
+}
+
+fn input() -> Vec<Vec<char>> {
+    safe_get_input_as_terrain(2025, 7)
+}

aoclp_solutions/src/y2025/day_07.rs

@@ -4,3 +4,4 @@ pub mod day_03;
 pub mod day_04;
 pub mod day_05;
 pub mod day_06;
+pub mod day_07;