2022 day14/rust: add solution

2022/day14/rust/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "rust_2022_14"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+aoc = { path = "../../../common/rust" }
+nom = "7.1.1"

2022/day14/rust/src/main.rs

@@ -0,0 +1,83 @@
+#![warn(clippy::pedantic)]
+
+use std::{collections::BTreeSet, io::stdin};
+
+use aoc::vec2::{Line, Vec2};
+use nom::{
+    bytes::complete::tag, character::complete::i32, multi::separated_list1,
+    sequence::separated_pair, IResult, Parser,
+};
+
+fn parse_points(s: &str) -> IResult<&str, Vec<Vec2>, ()> {
+    separated_list1(
+        tag(" -> "),
+        separated_pair(i32, tag(","), i32).map(Vec2::from),
+    )(s)
+}
+
+fn simulate(structures: BTreeSet<Vec2>, floor: Option<usize>) -> usize {
+    let mut points = structures;
+    let lowest = points.iter().map(|v| v.y).max().unwrap();
+    let start = Vec2::new(500, 0);
+
+    let mut pieces = 0;
+    'pieces: loop {
+        let mut pos = start;
+        'fall: loop {
+            let direction = [(0, 1), (-1, 1), (1, 1)]
+                .into_iter()
+                .map(Vec2::from)
+                .find(|&direction| !points.contains(&(pos + direction)));
+
+            if let Some(direction) = direction {
+                pos += direction;
+
+                match floor {
+                    Some(offset) => {
+                        if pos.y >= lowest + i32::try_from(offset).unwrap() - 1 {
+                            // landed on the floor
+                            break 'fall;
+                        }
+                    }
+                    None => {
+                        if pos.y >= lowest {
+                            // fell into the void
+                            break 'pieces;
+                        }
+                    }
+                }
+            } else {
+                // stuck
+                break 'fall;
+            }
+        }
+
+        points.insert(pos);
+        pieces += 1;
+
+        if pos == start {
+            // all filled up
+            break 'pieces;
+        }
+    }
+
+    pieces
+}
+
+fn main() {
+    let lines = stdin().lines().flat_map(|line| {
+        parse_points(&line.unwrap())
+            .unwrap()
+            .1
+            .windows(2)
+            .map(|x| Line {
+                start: x[0],
+                end: x[1],
+            })
+            .collect::<Vec<_>>()
+    });
+    let points: BTreeSet<Vec2> = lines.flat_map(|line| line.points().unwrap()).collect();
+
+    println!("{}", simulate(points.clone(), None));
+    println!("{}", simulate(points, Some(2)));
+}

Cargo.lock

@@ -593,6 +593,14 @@ dependencies = [
  "nom",
 ]
 
+[[package]]
+name = "rust_2022_14"
+version = "0.1.0"
+dependencies = [
+ "aoc",
+ "nom",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.11"

Cargo.toml

@@ -23,4 +23,5 @@ members = [
 	"2022/day11/rust",
 	"2022/day12/rust",
 	"2022/day13/rust",
+	"2022/day14/rust",
 ]