add day10

Author: mirsella

2024/day10/.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
+

2024/day10/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "day10"
+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]
+regex = { workspace = true }
+itertools = { workspace = true }
+pathfinding = { workspace = true }
+rayon = { workspace = true }
+indexmap = { workspace = true }

2024/day10/src/main.rs

@@ -0,0 +1,95 @@
+use pathfinding::matrix::Matrix;
+use std::collections::{HashMap, HashSet};
+
+fn part1(input: &str) -> usize {
+    let m = Matrix::from_rows(
+        input
+            .lines()
+            .map(|l| l.chars().map(|c| c.to_digit(10).unwrap() as u8)),
+    )
+    .unwrap();
+    fn parkour(m: &Matrix<u8>, trailends: &mut HashSet<(usize, usize)>, pos: (usize, usize)) {
+        if m[pos] == 9 {
+            trailends.insert(pos);
+            return;
+        }
+        for neighbor in m.neighbours(pos, false) {
+            if m[neighbor] == m[pos] + 1 {
+                parkour(m, trailends, neighbor);
+            }
+        }
+    }
+    let mut trailheads = HashMap::new();
+    let mut tmp_trailends = HashSet::new();
+    for (pos, &char) in m.items() {
+        if char != 0 {
+            continue;
+        }
+        parkour(&m, &mut tmp_trailends, pos);
+        trailheads.insert(pos, tmp_trailends.len());
+        tmp_trailends.clear();
+    }
+    trailheads.values().sum()
+}
+fn part2(input: &str) -> usize {
+    let m = Matrix::from_rows(
+        input
+            .lines()
+            .map(|l| l.chars().map(|c| c.to_digit(10).unwrap() as u8)),
+    )
+    .unwrap();
+    fn parkour(
+        m: &Matrix<u8>,
+        trailends: &mut HashSet<Vec<(usize, usize)>>,
+        mut current: Vec<(usize, usize)>,
+        pos: (usize, usize),
+    ) {
+        current.push(pos);
+        if m[pos] == 9 {
+            trailends.insert(current);
+            return;
+        }
+        for neighbor in m.neighbours(pos, false) {
+            if m[neighbor] == m[pos] + 1 {
+                parkour(m, trailends, current.clone(), neighbor);
+            }
+        }
+    }
+    let mut trailheads = HashMap::new();
+    let mut tmp_trailends = HashSet::new();
+    for (pos, &char) in m.items() {
+        if char != 0 {
+            continue;
+        }
+        parkour(&m, &mut tmp_trailends, Vec::new(), pos);
+        trailheads.insert(pos, tmp_trailends.len());
+        tmp_trailends.clear();
+    }
+    trailheads.values().sum()
+}
+
+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 = "89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732";
+    #[test]
+    fn part1() {
+        assert_eq!(super::part1(INPUT), 36);
+    }
+    #[test]
+    fn part2() {
+        assert_eq!(super::part2(INPUT), 81);
+    }
+}