Day 17a

.github/workflows/ci.yml

@@ -33,6 +33,7 @@ jobs:
             - day14
             - day15
             - day16
+            - day17
           part: [ a, b ]
     if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest

Cargo.toml

@@ -19,5 +19,6 @@ members = [
     "day14",
     "day15",
     "day16",
+    "day17",
 ]
 

day17/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "day17"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+aoc = { path = "../aoc" }
+color-eyre = "0.6.2"
+nom = "7.1.3"
+sqrid = "0.0.23"

day17/src/bin/day17a.rs

@@ -0,0 +1,78 @@
+// Copyright (C) 2023 Leandro Lisboa Penz <lpenz@lpenz.org>
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+
+use day17::*;
+
+use std::cmp::Reverse;
+use std::collections::BinaryHeap;
+use std::collections::HashSet;
+
+pub type Heat = u32;
+
+#[derive(Debug, Default, Hash, PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
+struct State {
+    pub pos: Pos,
+    pub lastdir: Option<Dir>,
+    pub dircount: usize,
+    pub heatacum: u32,
+}
+
+fn process(size: u16, bufin: impl BufRead) -> Result<u32> {
+    let input = parser::parse(bufin)?;
+    let gheat = Grid::try_from(input)?;
+    let mut frontier = BinaryHeap::<(Reverse<Heat>, State)>::default();
+    frontier.push((Reverse(0), State::default()));
+    let mut visited = HashSet::<(Pos, State)>::default();
+    let goal = Pos::try_from((size - 1, size - 1)).unwrap();
+    while let Some((_priority, st)) = frontier.pop() {
+        let pos = st.pos;
+        if visited.contains(&(pos, st)) {
+            continue;
+        }
+        if pos == goal {
+            return Ok(st.heatacum);
+        }
+        for dir in Dir::iter::<false>() {
+            if st.lastdir == Some(-dir) || (st.lastdir == Some(dir) && st.dircount >= 3) {
+                // Gets wobbly
+                continue;
+            }
+            if let Ok(newpos) = pos + dir {
+                let t = newpos.tuple();
+                if t.0 >= size || t.1 >= size {
+                    continue;
+                }
+                let heatacum = st.heatacum + gheat[newpos];
+                let dircount = if Some(dir) == st.lastdir {
+                    st.dircount + 1
+                } else {
+                    1
+                };
+                let newst = State {
+                    pos: newpos,
+                    lastdir: Some(dir),
+                    dircount,
+                    heatacum,
+                };
+                let dist = Pos::manhattan(&newpos, &goal) as u32;
+                let priority = Reverse(heatacum + dist);
+                frontier.push((priority, newst));
+            }
+        }
+        visited.insert((pos, st));
+    }
+    unreachable!();
+}
+
+#[test]
+fn test() -> Result<()> {
+    let start = std::time::Instant::now();
+    assert_eq!(process(13, EXAMPLE.as_bytes())?, 102);
+    println!("Elapsed: {}", elapsed(&start));
+    Ok(())
+}
+
+fn main() -> Result<()> {
+    do_main(|| process(141, stdin().lock()))
+}

day17/src/lib.rs

@@ -0,0 +1,74 @@
+// Copyright (C) 2023 Leandro Lisboa Penz <lpenz@lpenz.org>
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+
+pub use aoc::*;
+
+pub const EXAMPLE: &str = "2413432311323
+3215453535623
+3255245654254
+3446585845452
+4546657867536
+1438598798454
+4457876987766
+3637877979653
+4654967986887
+4564679986453
+1224686865563
+2546548887735
+4322674655533
+";
+
+pub type Cell = u32;
+
+pub mod parser {
+    use aoc::parser::*;
+
+    use super::*;
+
+    fn cell(input: &str) -> IResult<&str, Cell> {
+        let (input, val) = character::one_of("0123456789")(input)?;
+        Ok((input, val.to_digit(10).unwrap()))
+    }
+
+    fn line(input: &str) -> IResult<&str, Vec<Cell>> {
+        let (input, cells) = multi::many1(cell)(input)?;
+        let (input, _) = character::newline(input)?;
+        Ok((input, cells))
+    }
+
+    pub fn parse(mut bufin: impl BufRead) -> Result<Vec<Vec<Cell>>> {
+        aoc::parse_with!(multi::many1(line), bufin)
+    }
+}
+
+#[test]
+fn test() -> Result<()> {
+    let input = parser::parse(EXAMPLE.as_bytes())?;
+    assert_eq!(input.len(), 13);
+    assert_eq!(input[0].len(), 13);
+    Ok(())
+}
+
+pub use sqrid::Dir;
+pub type Sqrid = sqrid::sqrid_create!(141, 141, false);
+// pub type Sqrid = sqrid::sqrid_create!(13, 13, false);
+pub type Pos = sqrid::pos_create!(Sqrid);
+pub type Grid = sqrid::grid_create!(Sqrid, u32);
+
+pub type Griddir = sqrid::grid_create!(Sqrid, String);
+
+pub fn path_debug(_size: u16, gheat: &Grid, path: &[Dir]) {
+    let mut gheatacum = Grid::default();
+    let mut pos = Pos::TOP_LEFT;
+    let mut heat = 0;
+    let mut gdir = Griddir::default();
+    for dir in path {
+        gdir[pos] = dir.name_utf8().to_string();
+        pos = (pos + dir).unwrap();
+        heat += gheat[pos];
+        gheatacum[pos] = heat;
+    }
+    eprintln!("{:1}", gdir);
+    eprintln!("{:>4}", gheatacum);
+}