aoc2022 day08 part 2

src/aoc2022/day08/mod.rs

@@ -1,8 +1,7 @@
 const COLUMNS: usize = 99;
 const ROWS: usize = 99;
 
-pub fn task_one(input: &str) -> String {
+fn parse_into_grid(input: &str) -> [[u8; COLUMNS]; ROWS] {
-    let mut visible_trees = 0;
     let mut grid: [[u8; COLUMNS]; ROWS] = [[0; COLUMNS]; ROWS];
 
     for (i, line) in input.trim().lines().enumerate() {
@@ -13,6 +12,13 @@ pub fn task_one(input: &str) -> String {
 
     // println!("{:?}", grid);
 
+    grid
+}
+
+pub fn task_one(input: &str) -> String {
+    let mut visible_trees = 0;
+    let grid = parse_into_grid(&input);
+
     for i in 0..ROWS {
         for j in 0..COLUMNS {
             let tree = grid[i][j];
@@ -65,5 +71,63 @@ pub fn task_one(input: &str) -> String {
 }
 
 pub fn task_two(input: &str) -> String {
-    String::new()
+    let mut score = 0;
+    let grid = parse_into_grid(&input);
+
+    for i in 0..ROWS {
+        for j in 0..COLUMNS {
+            let tree = grid[i][j];
+
+            // check upwards
+            let mut visible_up = 0;
+            for k in (0..i).rev() {
+                visible_up += 1;
+                if grid[k][j] >= tree {
+                    break;
+                }
+            }
+
+            // check to the right
+            let mut visible_right = 0;
+            for k in (j + 1)..COLUMNS {
+                visible_right += 1;
+                if grid[i][k] >= tree {
+                    break;
+                }
+            }
+
+            // check downwards
+            let mut visible_down = 0;
+            for k in (i + 1)..ROWS {
+                visible_down += 1;
+                if grid[k][j] >= tree {
+                    break;
+                }
+            }
+
+            // check to the left
+            let mut visible_left = 0;
+            for k in (0..j).rev() {
+                visible_left += 1;
+                if grid[i][k] >= tree {
+                    break;
+                }
+            }
+
+            let new_score = visible_up * visible_right * visible_down * visible_left;
+            if new_score > score {
+                score = new_score;
+            }
+        }
+    }
+
+    score.to_string()
+}
+
+#[test]
+fn test_example() {
+    // set ROWS and COLUMNS to 5 for the test to pass
+    let input = "30373\n25512\n65332\n33549\n35390\n";
+
+    assert_eq!(task_two(&input), 8.to_string());
 }