Add solution for 2022 day 08

2022/Cargo.lock

@@ -36,6 +36,10 @@ dependencies = [
 name = "aoc-2022-07"
 version = "0.1.0"
 
+[[package]]
+name = "aoc-2022-08"
+version = "0.1.0"
+
 [[package]]
 name = "either"
 version = "1.8.0"

2022/Cargo.toml

@@ -7,6 +7,7 @@ members = [
     "./day-05",
     "./day-06",
     "./day-07",
+    "./day-08",
 ]
 
 

2022/README.md

@@ -11,7 +11,7 @@
 | 05  |   ✓    |   ✓    | [Rust]   |
 | 06  |   ✓    |   ✓    | [Rust]   |
 | 07  |   ✓    |   ✓    | [Rust]   |
-| 08  |        |        |          |
+| 08  |   ✓    |   ✓    | [Rust]   |
 | 09  |        |        |          |
 | 10  |        |        |          |
 | 11  |        |        |          |

2022/day-08/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "aoc-2022-08"
+version = "0.1.0"
+edition = "2021"
+
+
+[lib]
+test = false
+doctest = false
+
+
+[dependencies]

2022/day-08/Justfile

@@ -0,0 +1,5 @@
+@part PART INPUT_FILE="inputs/puzzle.txt":
+    cargo --quiet run --bin part_{{PART}} -- {{INPUT_FILE}}
+
+clean:
+    cargo clean

2022/day-08/inputs/puzzle.txt

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2022/day-08/inputs/test.txt

@@ -0,0 +1,5 @@
+30373
+25512
+65332
+33549
+35390

2022/day-08/src/bin/part_one.rs

@@ -0,0 +1,66 @@
+use std::{env, io};
+
+use aoc_2022_08::{parse_file, Tree, Trees};
+
+fn solve(path: &str) -> io::Result<usize> {
+    let trees = parse_file(path)?;
+
+    let mut count = 0;
+
+    for (x, tree_row) in trees.iter().enumerate() {
+        for (y, tree) in tree_row.iter().enumerate() {
+            if !is_hidden(&trees, tree, x, y) {
+                count += 1;
+            }
+        }
+    }
+
+    Ok(count)
+}
+
+fn is_hidden(trees: &Trees, tree: &Tree, x: usize, y: usize) -> bool {
+    // Edges are never hidden
+    if x == 0 || x == trees.len() - 1 || y == 0 || y == trees[x].len() - 1 {
+        return false;
+    }
+
+    let above_hidden = trees[..x].iter().any(|t| &t[y] >= tree);
+    let below_hidden = trees[x + 1..].iter().any(|t| &t[y] >= tree);
+    let left_hidden = trees[x][..y].iter().any(|t| t >= tree);
+    let right_hidden = trees[x][y + 1..].iter().any(|t| t >= tree);
+
+    above_hidden && below_hidden && left_hidden && right_hidden
+}
+
+fn main() -> io::Result<()> {
+    let infile_path = env::args().nth(1).expect("input file");
+
+    let result = solve(&infile_path)?;
+
+    println!("{result}");
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn sample() -> io::Result<()> {
+        let result = solve("inputs/test.txt")?;
+
+        assert_eq!(21, result);
+
+        Ok(())
+    }
+
+    #[test]
+    fn puzzle() -> io::Result<()> {
+        let result = solve("inputs/puzzle.txt")?;
+
+        assert_eq!(1679, result);
+
+        Ok(())
+    }
+}

2022/day-08/src/bin/part_two.rs

@@ -0,0 +1,85 @@
+use std::{env, io};
+
+use aoc_2022_08::{parse_file, Tree, Trees};
+
+fn solve(path: &str) -> io::Result<usize> {
+    let trees = parse_file(path)?;
+
+    let mut higest_score = 0;
+
+    for (x, tree_row) in trees.iter().enumerate() {
+        for (y, tree) in tree_row.iter().enumerate() {
+            let score = scenic_score(&trees, tree, x, y);
+
+            if score > higest_score {
+                higest_score = score;
+            }
+        }
+    }
+
+    Ok(higest_score)
+}
+
+fn distance_to_highest_tree<'a>(
+    trees: impl IntoIterator<Item = &'a Tree>,
+    origin_height: &Tree,
+) -> usize {
+    let mut score = 0;
+
+    for distant_height in trees {
+        score += 1;
+        if distant_height >= origin_height {
+            break;
+        }
+    }
+
+    score
+}
+
+fn scenic_score(trees: &Trees, tree: &Tree, x: usize, y: usize) -> usize {
+    // Edges always score 0
+    if x == 0 || x == trees.len() - 1 || y == 0 || y == trees[x].len() - 1 {
+        return 0;
+    }
+
+    let score_above = distance_to_highest_tree(trees[..x].iter().rev().map(|t| &t[y]), &tree);
+    let score_below = distance_to_highest_tree(trees[x + 1..].iter().map(|t| &t[y]), &tree);
+    let score_left = distance_to_highest_tree(trees[x][..y].iter().rev(), &tree);
+    let score_right = distance_to_highest_tree(&trees[x][y + 1..], &tree);
+
+    let score = score_above * score_below * score_left * score_right;
+
+    score
+}
+
+fn main() -> io::Result<()> {
+    let infile_path = env::args().nth(1).expect("input file");
+    let result = solve(&infile_path)?;
+
+    println!("{result}");
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn sample() -> io::Result<()> {
+        let result = solve("inputs/test.txt")?;
+
+        assert_eq!(8, result);
+
+        Ok(())
+    }
+
+    #[test]
+    fn puzzle() -> io::Result<()> {
+        let result = solve("inputs/puzzle.txt")?;
+
+        assert_eq!(536625, result);
+
+        Ok(())
+    }
+}

2022/day-08/src/lib.rs

@@ -0,0 +1,27 @@
+use std::{
+    fs::File,
+    io::{self, BufRead, BufReader},
+    path::Path,
+};
+
+pub type Tree = u8;
+pub type Trees = Vec<Vec<Tree>>;
+
+pub fn parse_file<P>(path: P) -> io::Result<Trees>
+where
+    P: AsRef<Path>,
+{
+    let mut trees = Trees::new();
+
+    let file = File::open(path)?;
+    for line in BufReader::new(file).lines() {
+        let line = line?;
+        let tree_row = line
+            .chars()
+            .map(|tree| tree.to_digit(10).unwrap() as u8)
+            .collect();
+        trees.push(tree_row);
+    }
+
+    Ok(trees)
+}

README.md

@@ -9,4 +9,4 @@
 -   [2019](2019/README.md) (0% completed)
 -   [2020](2020/README.md) (20% completed)
 -   [2021](2021/README.md) (68% completed)
--   [2022](2022/README.md) (28% completed)
+-   [2022](2022/README.md) (32% completed)