1 files changed, 42 insertions, 0 deletions

diff --git a/2022/08/a.rs b/2022/08/a.rs
new file mode 100644
index 0000000..b145486
--- /dev/null
+++ b/2022/08/a.rs
@@ -0,0 +1,42 @@
+use std::cmp::max;
+mod common;
+use common::*;
+
+fn mark_visible(grid: &mut Grid) {
+    let update = |elem: &mut (i8, bool), m: &mut i8| {
+        elem.1 = elem.1 || elem.0 > *m;
+        *m = max(*m, elem.0);
+    };
+
+    for row in &mut *grid {
+        // From left
+        let mut m = -1;
+        for t in &mut *row { update(t, &mut m); }
+
+        // From right
+        let mut m = -1;
+        for t in &mut row.iter_mut().rev() { update(t, &mut m); }
+    }
+
+    for j in 0..grid[0].len() {
+        // From top
+        let mut m = -1;
+        for i in 0..grid.len() { update(&mut grid[i][j], &mut m); }
+
+        // From bottom
+        let mut m = -1;
+        for i in (0..grid.len()).rev() { update(&mut grid[i][j], &mut m); }
+    }
+}
+
+fn count_visible(grid: &Grid) -> usize {
+    grid.iter()
+        .map(|row| row.iter().filter(|c| c.1).count())
+        .sum()
+}
+
+fn main() {
+    let mut grid = read_grid_from_stdin();
+    mark_visible(&mut grid);
+    println!("{}", count_visible(&grid));
+}