add day23

2023/Cargo.toml

@@ -24,7 +24,7 @@ members = [
   "day20",
   "day21",
   # "day22",
-  # "day23",
+  "day23",
   # "day24",
   # "day25",
 ]

2023/day15/src/main.rs

@@ -1,5 +1,3 @@
-use std::{collections::HashMap, ops::Index};
-
 use indexmap::IndexMap;
 
 fn hash(input: &str) -> usize {

2023/day23/.gitignore

@@ -0,0 +1,19 @@
+input.txt
+flamegraph.svg
+perf.data*
+### Rust
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb
+

2023/day23/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "day23"
+authors = ["mirsella <[email protected]>"]
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+grid = "0.13.0"

2023/day23/build.rs

@@ -0,0 +1,28 @@
+use std::fs::File;
+use std::io::{self, Read};
+use std::path::PathBuf;
+use std::{env, fs};
+
+fn replace_in_file(file_path: &PathBuf, old: &str, new: &str) -> io::Result<()> {
+    let mut contents = String::new();
+    File::open(file_path)?.read_to_string(&mut contents)?;
+    let new_contents = contents.replace(old, new);
+    if contents != new_contents {
+        println!("Updating {}", file_path.display());
+        fs::write(file_path, new_contents)?;
+    }
+    Ok(())
+}
+
+fn main() -> io::Result<()> {
+    let pkg_name = env::var("CARGO_PKG_NAME").unwrap();
+    replace_in_file(
+        &"../Cargo.toml".into(),
+        &format!("# \"{pkg_name}\""),
+        &format!("\"{pkg_name}\""),
+    )?;
+
+    replace_in_file(&"./Cargo.toml".into(), "\n[workspace]", "")?;
+
+    Ok(())
+}

2023/day23/src/main.rs

@@ -0,0 +1,93 @@
+use grid::Grid;
+
+const DIRECTIONS: [(isize, isize, char); 4] =
+    [(0, 1, 'v'), (1, 0, '>'), (0, -1, '^'), (-1, 0, '<')];
+
+fn dfs(grid: &mut Grid<char>, (x, y): (isize, isize), path: usize, paths: &mut Vec<usize>) {
+    // found the end
+    if y == grid.rows() as isize - 1 {
+        paths.push(path);
+        return;
+    }
+
+    for (dx, dy, c) in DIRECTIONS.iter() {
+        let nx = x + dx;
+        let ny = y + dy;
+        match grid.get(ny, nx).copied() {
+            Some(before) if before == '.' || before == *c => {
+                // print_grid(grid);
+                *grid.get_mut(ny, nx).unwrap() = 'O';
+                dfs(grid, (nx, ny), path + 1, paths);
+                *grid.get_mut(ny, nx).unwrap() = before;
+            }
+            _ => (),
+        }
+    }
+}
+
+fn part1(input: &str) -> usize {
+    let mut grid = Grid::from_vec(
+        input.replace('\n', "").chars().collect(),
+        input.find('\n').unwrap(),
+    );
+    let start_x = grid.iter_row(0).position(|&c| c == '.').unwrap();
+    let mut result = Vec::new();
+    dfs(&mut grid, (0, start_x as isize), 0, &mut result);
+    *result.iter().max().unwrap()
+}
+
+fn part2(input: &str) -> usize {
+    let mut grid = Grid::from_vec(
+        input
+            .replace('\n', "")
+            .replace(['<', '>', '^', 'v'], ".")
+            .chars()
+            .collect(),
+        input.find('\n').unwrap(),
+    );
+    let start_x = grid.iter_row(0).position(|&c| c == '.').unwrap();
+    let mut result = Vec::new();
+    dfs(&mut grid, (0, start_x as isize), 0, &mut result);
+    *result.iter().max().unwrap()
+}
+
+fn main() {
+    let input = include_str!("../input.txt");
+    println!("Part 1: {}", part1(input));
+    println!("Part 2: {}", part2(input));
+}
+
+#[cfg(test)]
+mod tests {
+    const INPUT: &str = "#.#####################
+#.......#########...###
+#######.#########.#.###
+###.....#.>.>.###.#.###
+###v#####.#v#.###.#.###
+###.>...#.#.#.....#...#
+###v###.#.#.#########.#
+###...#.#.#.......#...#
+#####.#.#.#######.#.###
+#.....#.#.#.......#...#
+#.#####.#.#.#########v#
+#.#...#...#...###...>.#
+#.#.#v#######v###.###v#
+#...#.>.#...>.>.#.###.#
+#####v#.#.###v#.#.###.#
+#.....#...#...#.#.#...#
+#.#########.###.#.#.###
+#...###...#...#...#.###
+###.###.#.###v#####v###
+#...#...#.#.>.>.#.>.###
+#.###.###.#.###.#.#v###
+#.....###...###...#...#
+#####################.#";
+    #[test]
+    fn part1() {
+        assert_eq!(super::part1(INPUT), 94);
+    }
+    #[test]
+    fn part2() {
+        assert_eq!(super::part2(INPUT), 154);
+    }
+}