gamp

2023/Cargo.toml

@@ -18,7 +18,7 @@ members = [
   "day14",
   "day15",
   "day16",
-  # "day17",
+  "day17",
   # "day18",
   # "day19",
   # "day20",

2023/day17/.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/day17/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "day17"
+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]
+pathfinding = "4.6.0"

2023/day17/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/day17/src/main.rs

@@ -0,0 +1,94 @@
+use pathfinding::{directed::dijkstra::dijkstra, matrix::Matrix};
+
+fn pathfind(input: &str, min: usize, max: usize) -> usize {
+    let grid = Matrix::from_rows(
+        input
+            .lines()
+            .map(|l| l.chars().map(|c| c.to_digit(10).unwrap())),
+    )
+    .unwrap();
+
+    let result = dijkstra(
+        &((0, 0), (0, 0), 0),
+        |&(pos, (direction_x, direction_y), consecutive_count)| {
+            let mut moves = Vec::new();
+            let mut add_moves = |direction, consecutive_count| {
+                if let Some(new_pos) = grid.move_in_direction(pos, direction) {
+                    moves.push(((new_pos, direction, consecutive_count), grid[new_pos]));
+                };
+            };
+            if consecutive_count < max {
+                add_moves((direction_x, direction_y), consecutive_count + 1);
+            }
+            if consecutive_count >= min {
+                add_moves((-direction_y, -direction_x), 1);
+                add_moves((direction_y, direction_x), 1);
+            } else if consecutive_count == 0 {
+                add_moves((1, 0), 1);
+                add_moves((0, 1), 1);
+            }
+            moves
+        },
+        |pos| pos.0 == (grid.rows - 1, grid.columns - 1) && pos.2 >= min,
+    )
+    .unwrap();
+    for (x, row) in grid.iter().enumerate() {
+        for (y, digit) in row.iter().enumerate() {
+            if result.0.iter().any(|p| p.0 == (x, y)) {
+                print!("#");
+            } else {
+                print!("{}", digit);
+            }
+        }
+        println!();
+    }
+    result.1 as usize
+}
+
+fn part1(input: &str) -> usize {
+    pathfind(input, 1, 3)
+}
+
+fn part2(input: &str) -> usize {
+    pathfind(input, 4, 10)
+}
+
+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 = "2413432311323
+3215453535623
+3255245654254
+3446585845452
+4546657867536
+1438598798454
+4457876987766
+3637877979653
+4654967986887
+4564679986453
+1224686865563
+2546548887735
+4322674655533";
+    const INPUT2: &str = "111111111111
+999999999991
+999999999991
+999999999991
+999999999991";
+    #[test]
+    fn part1() {
+        assert_eq!(super::part1(INPUT), 102);
+    }
+    #[test]
+    fn part2() {
+        assert_eq!(super::part2(INPUT), 94);
+    }
+    #[test]
+    fn part2_2() {
+        assert_eq!(super::part2(INPUT2), 71);
+    }
+}