1 files changed, 179 insertions, 0 deletions
diff --git a/2022/Rust/src/day8.rs b/2022/Rust/src/day8.rs
new file mode 100644
index 0000000..6a337f6
--- /dev/null
+++ b/2022/Rust/src/day8.rs
@@ -0,0 +1,179 @@
+enum Direction {
+    Up,
+    Down,
+    Right,
+    Left,
+}
+
+impl Direction {
+    fn new(dir: (i32, i32)) -> Self {
+        match dir {
+            (0, 1) => Direction::Up,
+            (1, 0) => Direction::Right,
+            (0, -1) => Direction::Left,
+            (-1, 0) => Direction::Down,
+            _ => unreachable!(),
+        }
+    }
+}
+
+fn is_visible(grd: &Vec<&str>, direction: &Direction, visible: &mut Vec<Vec<bool>>) {
+    let mut max_height = 0;
+    match direction {
+        Direction::Up => {
+            for j in 0..grd[0].len() {
+                let mut cur_max_h: i32 = -1;
+                for i in (0..grd.len()).rev() {
+                    if (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32 > cur_max_h {
+                        cur_max_h = (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32;
+                        visible[i][j] = true;
+                    }
+                }
+            }
+        }
+        Direction::Down => {
+            for j in 0..grd[0].len() {
+                let mut cur_max_h: i32 = -1;
+                for i in 0..grd.len() {
+                    if (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32 > cur_max_h {
+                        cur_max_h = (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32;
+                        visible[i][j] = true;
+                    }
+                }
+            }
+        }
+        Direction::Right => {
+            for i in 0..grd.len() {
+                let mut cur_max_h: i32 = -1;
+                for j in 0..grd[0].len() {
+                    if (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32 > cur_max_h {
+                        cur_max_h = (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32;
+                        visible[i][j] = true;
+                    }
+                }
+            }
+        }
+        Direction::Left => {
+            for i in 0..grd.len() {
+                let mut cur_max_h: i32 = -1;
+                for j in (0..grd[0].len()).rev() {
+                    if (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32 > cur_max_h {
+                        cur_max_h = (grd[i].chars().nth(j).unwrap() as u8 - '0' as u8) as i32;
+                        visible[i][j] = true;
+                    }
+                }
+            }
+        }
+    }
+}
+
+fn is_valid_idx(pos: (usize, usize), size: (usize, usize), direction: &Direction) -> bool {
+    match direction {
+        Direction::Up => pos.0 as i32 - 1 >= 0,
+        Direction::Down => pos.0 + 1 < size.0,
+        Direction::Right => pos.1 + 1 < size.1,
+        Direction::Left => pos.1 as i32 - 1 >= 0,
+    }
+}
+
+fn count_vis_right(pos: (usize, usize), grd: &Vec<&str>) -> usize {
+    let mut cnt = 0;
+    if is_valid_idx(pos, (grd.len(), grd[0].len()), &Direction::Right) {
+        let ch = grd[pos.0].chars().nth(pos.1).unwrap() as u8;
+        for i in (pos.1 + 1)..grd[0].len() {
+            if grd[pos.0].chars().nth(i).unwrap() as u8 >= ch {
+                cnt += 1;
+                break;
+            }
+            cnt += 1
+        }
+    }
+    cnt
+}
+fn count_vis_left(pos: (usize, usize), grd: &Vec<&str>) -> usize {
+    let mut cnt = 0;
+    if is_valid_idx(pos, (grd.len(), grd[0].len()), &Direction::Left) {
+        let ch = grd[pos.0].chars().nth(pos.1).unwrap() as u8;
+        for i in (0..=(pos.1 - 1)).rev() {
+            if grd[pos.0].chars().nth(i).unwrap() as u8 >= ch {
+                cnt += 1;
+                break;
+            }
+            cnt += 1
+        }
+    }
+    cnt
+}
+
+fn count_vis_up(pos: (usize, usize), grd: &Vec<&str>) -> usize {
+    let mut cnt = 0;
+    if is_valid_idx(pos, (grd.len(), grd[0].len()), &Direction::Up) {
+        let ch = grd[pos.0].chars().nth(pos.1).unwrap() as u8;
+        // print!("{:?}  ", pos);
+        for i in (0..=(pos.0 - 1)).rev() {
+            // print!("{:?}, ", (i, pos.1));
+            if grd[i].chars().nth(pos.1).unwrap() as u8 >= ch {
+                cnt += 1;
+                break;
+            }
+            cnt += 1
+        }
+        // println!()
+    }
+    cnt
+}
+fn count_vis_down(pos: (usize, usize), grd: &Vec<&str>) -> usize {
+    let mut cnt = 0;
+    let ch = grd[pos.0].chars().nth(pos.1).unwrap() as u8;
+    if is_valid_idx(pos, (grd.len(), grd[0].len()), &Direction::Down) {
+        for i in (pos.0 + 1)..grd.len() {
+            if grd[i].chars().nth(pos.1).unwrap() as u8 >= ch {
+                cnt += 1;
+                break;
+            }
+            cnt += 1
+        }
+    }
+    cnt
+}
+
+fn count_visible(pos: (usize, usize), grd: &Vec<&str>) -> usize {
+    count_vis_up(pos, grd)
+        * count_vis_down(pos, grd)
+        * count_vis_left(pos, grd)
+        * count_vis_right(pos, grd)
+}
+
+fn solve_part_one(data: &str) -> usize {
+    let grid: Vec<_> = data.lines().collect();
+    let dx: [i32; 4] = [0, 1, 0, -1];
+    let dy: [i32; 4] = [1, 0, -1, 0];
+    let mut visible: Vec<Vec<bool>> = vec![vec![false; grid[0].len()]; grid.len()];
+
+    for i in 0..4 {
+        let direction = Direction::new((dx[i], dy[i]));
+        is_visible(&grid, &direction, &mut visible)
+    }
+    visible.iter().flatten().filter(|&x| *x == true).count()
+}
+
+fn solve_part_two(data: &str) -> usize {
+    let grid: Vec<_> = data.lines().collect();
+
+    let mut max_score = 0;
+    for i in 0..grid.len() {
+        for j in 0..grid[0].len() {
+            max_score = std::cmp::max(max_score, count_visible((i, j), &grid));
+        }
+    }
+    max_score
+}
+
+fn main() {
+    let data_test = include_str!("../input/day8.test");
+    let data_prod = include_str!("../input/day8.prod");
+    println!("{}", solve_part_one(data_test));
+    println!("{}", solve_part_one(data_prod));
+    println!("{}", solve_part_two(data_test));
+    println!("{}", solve_part_two(data_prod));
+}