day 8

note: I don't really like this solution but whatever fuck it burn
:flame:

src/day08.rs

@@ -0,0 +1,79 @@
+use itertools::Itertools;
+
+pub fn process_part_1(input: &str) -> usize {
+    let trees = parse_trees(input);
+
+    let rows = trees.len();
+    let cols = trees[0].len();
+    (0..rows)
+        .cartesian_product(0..cols)
+        .filter(|&(row, col)| {
+            let height = trees[row][col];
+            (0..row).all(|i| trees[i][col] < height) // up
+                || (row + 1..rows).all(|i| trees[i][col] < height) // down
+                || (0..col).all(|i| trees[row][i] < height) // left
+                || (col + 1..cols).all(|i| trees[row][i] < height) // right
+        })
+        .count()
+}
+
+pub fn process_part_2(input: &str) -> usize {
+    let trees = parse_trees(input);
+    let rows = trees.len();
+    let cols = trees[0].len();
+    (0..rows)
+        .cartesian_product(0..cols)
+        .map(|(row, col)| {
+            let height = trees[row][col];
+
+            let up = match (0..row).rev().position(|i| trees[i][col] >= height) {
+                Some(n) => n + 1,
+                None => row,
+            };
+            let down = match (row + 1..rows).position(|i| trees[i][col] >= height) {
+                Some(n) => n + 1,
+                None => rows - row - 1,
+            };
+            let left = match (0..col).rev().position(|i| trees[row][i] >= height) {
+                Some(n) => n + 1,
+                None => col,
+            };
+            let right = match (col + 1..cols).position(|i| trees[row][i] >= height) {
+                Some(n) => n + 1,
+                None => cols - col - 1,
+            };
+
+            up * down * left * right
+        })
+        .max()
+        .unwrap()
+}
+
+fn parse_trees(input: &str) -> Vec<Vec<u8>> {
+    input
+        .trim()
+        .split("\n")
+        .map(|i| i.chars().map(|c| c.to_digit(10).unwrap() as u8).collect())
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const INPUT: &str = "30373
+25512
+65332
+33549
+35390";
+
+    #[test]
+    fn day1() {
+        assert_eq!(process_part_1(INPUT), 21);
+    }
+
+    #[test]
+    fn day2() {
+        assert_eq!(process_part_2(INPUT), 8);
+    }
+}