day 8

day08/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day08"
+version = "0.1.0"

day08/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "day08"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day08/src/main.rs

@@ -0,0 +1,83 @@
+fn main() {
+    let f = std::fs::read_to_string("/dev/stdin").unwrap();
+    let rows = f
+        .lines()
+        .map(|c| {
+            c.chars()
+                .map(|c| c.to_digit(10).unwrap() as usize)
+                .collect::<Vec<usize>>()
+        })
+        .collect::<Vec<Vec<usize>>>();
+
+    let mut cols: Vec<Vec<usize>> = Vec::new();
+    for i in 0..rows.len() {
+        let mut col = Vec::new();
+        for j in 0..rows.len() {
+            col.push(*rows.get(j).unwrap().get(i).unwrap());
+        }
+        cols.push(col);
+    }
+
+    let mut total_visible = 0;
+    let mut scenic_score = 0;
+
+    for (row_num, row) in rows.iter().enumerate() {
+        if row_num == 0 {
+            total_visible += (row.len() - 1) * 4; // perimeter
+            continue;
+        }
+        if row_num == rows.len() - 1 {
+            break;
+        }
+
+        for (col_num, col) in row.get(0..row.len() - 1).unwrap().iter().enumerate() {
+            if col_num == 0 {
+                continue;
+            }
+            let before_row = row.get(0..col_num).unwrap();
+            let after_row = row.get(col_num + 1..).unwrap();
+            let this_col = cols.get(col_num).unwrap();
+            let before_col = this_col.get(0..row_num).unwrap();
+            let after_col = this_col.get(row_num + 1..).unwrap();
+
+            let visible_before = get_viewing_distance(*col, before_row, true);
+            let visible_after = get_viewing_distance(*col, after_row, false);
+            let visible_above = get_viewing_distance(*col, before_col, true);
+            let visible_below = get_viewing_distance(*col, after_col, false);
+            let score = visible_before * visible_after * visible_above * visible_below;
+            if score > scenic_score {
+                scenic_score = score;
+            }
+
+            if before_row.iter().filter(|t| t >= &col).count() == 0
+                || after_row.iter().filter(|t| t >= &col).count() == 0
+                || before_col.iter().filter(|t| t >= &col).count() == 0
+                || after_col.iter().filter(|t| t >= &col).count() == 0
+            {
+                total_visible += 1;
+            }
+        }
+    }
+
+    println!("{}, {}", total_visible, scenic_score);
+}
+
+fn get_viewing_distance(height: usize, view: &[usize], reverse_order: bool) -> usize {
+    let mut visible = 0;
+    if reverse_order {
+        for tree in view.iter().rev() {
+            visible += 1;
+            if tree >= &height {
+                break;
+            }
+        }
+    } else {
+        for tree in view {
+            visible += 1;
+            if tree >= &height {
+                break;
+            }
+        }
+    }
+    visible
+}

day08/test

@@ -0,0 +1,5 @@
+30373
+25512
+65332
+33549
+35390