Day10 - part 1

diff --git a/src/day10.rs b/src/day10.rs
new file mode 100644 (file)
index 0000000..57b56a8
--- /dev/null
+++ b/src/day10.rs
@@ -0,0 +1,146 @@
+use std::error::Error;
+use std::path::Path;
+use std::collections::{HashMap, HashSet};
+
+struct Puzzle {
+    map: HashMap<(isize, isize), u8>,
+    start_pos: Vec<(isize, isize)>,
+}
+
+impl Puzzle {
+    pub fn new(input: &str) -> Self {
+        let mut map = HashMap::new();
+        let mut start_pos = Vec::new();
+        input.lines().enumerate()
+            .for_each(|(r, l)| {
+                l.as_bytes().into_iter().enumerate()
+                    .for_each(|(c, b)| {
+                        if *b != b'.' {
+                            map.insert((r as isize, c as isize), *b);
+                            if *b == b'0' {
+                                start_pos.push((r as isize, c as isize));
+                            }
+                        }
+                    });
+            });
+        Self { map, start_pos }
+    }
+
+    fn score(self: &Self, pos: (isize, isize), value: u8, visited: &mut HashSet<(isize, isize)>) -> u32 {
+        [(-1,0), (0,1), (1,0), (0,-1)].iter()
+            .map(|dij| (pos.0 + dij.0 as isize, pos.1 + dij.1 as isize))
+            .map(|new_pos| {
+                match self.map.get(&new_pos) {
+                    Some(&value_next) => {
+                        if value_next == value + 1 {
+                            if value_next == b'9' && !visited.contains(&new_pos) {
+                                visited.insert(new_pos);
+                                1
+                            }
+                            else {
+                                self.score(new_pos, value_next, visited)
+                            }
+                        }
+                        else {
+                            0
+                        }
+                    },
+                    _ => { 0 }
+                }
+            })
+            .sum()
+    }
+}
+
+fn run_part1(input: &str) -> Result<u32, Box<dyn Error>> {
+    println!("Running {} - part 1", get_day());
+
+    let puzzle = Puzzle::new(input);
+    let res = puzzle.start_pos.iter()
+        .map(|pos| {
+            let mut visited = HashSet::new();
+            puzzle.score(*pos, b'0', &mut visited)
+        })
+        .sum();
+
+    Ok(res)
+}
+
+fn run_part2(input: &str) -> Result<u32, Box<dyn Error>> {
+    println!("Running {} - part 2", get_day());
+
+    Ok(0)
+}
+
+pub fn run(input: &str) -> Result<(), Box<dyn Error>> {
+    let res = run_part1(&input)?;
+    println!("{res}");
+
+    let res = run_part2(&input)?;
+    println!("{res}");
+
+    Ok(())
+}
+
+fn get_day() -> String {
+    let filename = file!();
+    Path::new(filename).file_stem().unwrap().to_str().unwrap().to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    static TEXT_INPUT_0: &str = "\
+0123
+1234
+8765
+9876";
+    static TEXT_INPUT_1: &str = "\
+...0...
+...1...
+...2...
+6543456
+7.....7
+8.....8
+9.....9";
+    static TEXT_INPUT_2: &str = "\
+..90..9
+...1.98
+...2..7
+6543456
+765.987
+876....
+987....";
+    static TEXT_INPUT_3: &str = "\
+10..9..
+2...8..
+3...7..
+4567654
+...8..3
+...9..2
+.....01";
+    static TEXT_INPUT: &str = "\
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732";
+
+    #[test]
+    fn test_part1() {
+        assert_eq!(1, run_part1(TEXT_INPUT_0).unwrap());
+        assert_eq!(2, run_part1(TEXT_INPUT_1).unwrap());
+        assert_eq!(4, run_part1(TEXT_INPUT_2).unwrap());
+        assert_eq!(3, run_part1(TEXT_INPUT_3).unwrap());
+        assert_eq!(36, run_part1(TEXT_INPUT).unwrap());
+    }
+
+    #[test]
+    fn test_part2() {
+        assert_eq!(0, run_part2(TEXT_INPUT).unwrap());
+    }
+}

diff --git a/src/main.rs b/src/main.rs
index a66cb4d48129c4b6bd24932b49a791c14ca86ed5..52ca4cc28661310076756c5328ed6398938d9964 100644 (file)
--- a/src/main.rs
+++ b/src/main.rs
@@ -13,6 +13,7 @@ pub mod day06;
 pub mod day07;
 pub mod day08;
 pub mod day09;
+pub mod day10;
 
 fn main() {
     let args: Vec<String> = env::args().collect();
@@ -44,6 +45,7 @@ fn run(day: &str, input_file: &str) -> Result<(), Box<dyn Error>> {
         "day07" => day07::run(&input)?,
         "day08" => day08::run(&input)?,
         "day09" => day09::run(&input)?,
+        "day10" => day10::run(&input)?,
         _ => return Err(format!("unknown or unimplemented day \"{day}\"").into()),
     }
     Ok(())