2022 day8/rust: add solution

2022/day8/rust/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "rust_2022_08"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+aoc = { path = "../../../common/rust" }

2022/day8/rust/src/main.rs

@@ -0,0 +1,74 @@
+#![warn(clippy::pedantic)]
+
+use std::io::{stdin, Read};
+
+use aoc::*;
+
+#[derive(Debug, Clone, Copy)]
+struct Tree {
+    height: u32,
+    visible: bool,
+    score: usize,
+}
+
+fn make_visible<'a>(trees: impl IntoIterator<Item = &'a mut Tree>) {
+    let mut seen: Vec<Tree> = Vec::new();
+    let mut highest: Option<Tree> = None;
+
+    for tree in trees {
+        let update = match highest {
+            None => true,
+            Some(highest) => tree.height > highest.height,
+        };
+
+        if update {
+            tree.visible = true;
+            highest = Some(*tree);
+        }
+
+        let mut score = 0;
+        for t in seen.iter().rev() {
+            score += 1;
+            if t.height >= tree.height {
+                break;
+            }
+        }
+        tree.score *= score;
+        seen.push(*tree);
+    }
+}
+
+fn main() {
+    let mut data = String::new();
+    stdin().read_to_string(&mut data).unwrap();
+
+    let mut grid: Vec<Vec<Tree>> = data
+        .lines()
+        .map(|line| {
+            line.chars()
+                .map(|c| Tree {
+                    height: c.to_digit(10).unwrap(),
+                    visible: false,
+                    score: 1,
+                })
+                .collect()
+        })
+        .collect();
+
+    for line in &mut grid {
+        make_visible(line.iter_mut());
+        make_visible(line.iter_mut().rev());
+    }
+
+    let width = grid[0].len();
+    for i in 0..width {
+        make_visible(grid.iter_mut().map(|l| &mut l[i]));
+        make_visible(grid.iter_mut().map(|l| &mut l[i]).rev());
+    }
+
+    println!("{:?}", grid.iter().flatten().filter(|&t| t.visible).count());
+    println!(
+        "{:?}",
+        grid.iter().flatten().map(|t| t.score).max().unwrap()
+    );
+}

Cargo.lock

@@ -517,6 +517,13 @@ dependencies = [
  "aoc",
 ]
 
+[[package]]
+name = "rust_2022_08"
+version = "0.1.0"
+dependencies = [
+ "aoc",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.11"

Cargo.toml

@@ -17,4 +17,5 @@ members = [
 	"2022/day5/rust",
 	"2022/day6/rust",
 	"2022/day7/rust",
+	"2022/day8/rust",
 ]