Solve day 8

src/bin/08.rs

@@ -0,0 +1,115 @@
+use std::ops::Add;
+
+use aoc2022::*;
+use itertools::Itertools;
+
+const INPUT: &str = include_str!("../../input/08");
+
+fn main() {
+    let forest = Forest::from_input();
+    solved_level_1(forest.level1());
+    solved_level_2(forest.level2());
+}
+
+#[derive(Debug)]
+struct Forest(Vec<Vec<i64>>);
+
+impl Forest {
+    fn from_input() -> Self {
+        let trees = INPUT
+            .lines()
+            .map(|line| {
+                line.chars()
+                    .map(|c| c.to_digit(10).unwrap() as i64)
+                    .collect_vec()
+            })
+            .collect_vec();
+        Self(trees)
+    }
+
+    fn iter(&self) -> impl Iterator<Item = (usize, usize)> {
+        let x = 0..self.0[0].len();
+        let y = 0..self.0.len();
+        (x).cartesian_product(y)
+    }
+
+    fn level1(&self) -> usize {
+        self.iter().filter(|&(x, y)| self.is_visible(x, y)).count()
+    }
+
+    fn level2(&self) -> i64 {
+        self.iter().map(|(x, y)| self.score(x, y)).max().unwrap()
+    }
+
+    fn is_visible(&self, x: usize, y: usize) -> bool {
+        let height = self.0[y][x];
+
+        let mut right_visible = true;
+        for xx in x.add(1)..self.0[0].len() {
+            if self.0[y][xx] >= height {
+                right_visible = false;
+            }
+        }
+
+        let mut left_visible = true;
+        for xx in 0..x {
+            if self.0[y][xx] >= height {
+                left_visible = false;
+            }
+        }
+
+        let mut down_visible = true;
+        for yy in y.add(1)..self.0.len() {
+            if self.0[yy][x] >= height {
+                down_visible = false;
+            }
+        }
+
+        let mut up_visible = true;
+        for yy in 0..y {
+            if self.0[yy][x] >= height {
+                up_visible = false;
+            }
+        }
+
+        right_visible || left_visible || down_visible || up_visible
+    }
+
+    fn score(&self, x: usize, y: usize) -> i64 {
+        let height = self.0[y][x];
+
+        let mut right = 0;
+        for xx in x.add(1)..self.0[0].len() {
+            right += 1;
+            if self.0[y][xx] >= height {
+                break;
+            }
+        }
+
+        let mut left = 0;
+        for xx in (0..x).rev() {
+            left += 1;
+            if self.0[y][xx] >= height {
+                break;
+            }
+        }
+
+        let mut down = 0;
+        for yy in y.add(1)..self.0.len() {
+            down += 1;
+            if self.0[yy][x] >= height {
+                break;
+            }
+        }
+
+        let mut up = 0;
+        for yy in (0..y).rev() {
+            up += 1;
+            if self.0[yy][x] >= height {
+                break;
+            }
+        }
+
+        right * left * down * up
+    }
+}