day 8

src/days/day8.rs

@@ -0,0 +1,66 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+
+#[aoc_generator(day8)]
+fn generator(input: &str) -> Vec<Vec<u32>> {
+    input
+        .lines()
+        .map(|l| l.trim().chars().map(|v| v.to_digit(10).unwrap()).collect())
+        .collect()
+}
+
+#[aoc(day8, part1)]
+fn part1_indexing(input: &[Vec<u32>]) -> u32 {
+    let mut count = 0;
+
+    for i in 0..input.len() {
+        for j in 0..input[i].len() {
+            let v = input[i][j];
+
+            if input[i][..j].iter().all(|&v2| v2 < v)
+                || input[i][j + 1..].iter().all(|&v2| v2 < v)
+                || input[..i].iter().map(|v| v[j]).all(|v2| v2 < v)
+                || input[i + 1..].iter().map(|v| v[j]).all(|v2| v2 < v)
+            {
+                count += 1;
+            }
+        }
+    }
+
+    count
+}
+
+fn take_until_inclusive<I: Iterator>(v: I, mut f: impl FnMut(&I::Item) -> bool) -> impl Iterator {
+    let mut should_stop = false;
+    v.take_while(move |item| {
+        if should_stop {
+            false
+        } else {
+            should_stop = f(item);
+            true
+        }
+    })
+}
+
+#[aoc(day8, part2)]
+fn part2(input: &[Vec<u32>]) -> usize {
+    let mut highest = 0;
+
+    for i in 0..input.len() {
+        for j in 0..input[i].len() {
+            let v = input[i][j];
+
+            let left = take_until_inclusive(input[i][..j].iter().rev(), |&&v2| v2 >= v).count();
+            let right = take_until_inclusive(input[i][j + 1..].iter(), |&&v2| v2 >= v).count();
+            let up =
+                take_until_inclusive(input[..i].iter().rev().map(|v| v[j]), |&v2| v2 >= v).count();
+            let down =
+                take_until_inclusive(input[i + 1..].iter().map(|v| v[j]), |&v2| v2 >= v).count();
+
+            let scenic_score = left * right * up * down;
+
+            highest = highest.max(scenic_score);
+        }
+    }
+
+    highest
+}

src/lib.rs

@@ -8,6 +8,7 @@ mod days {
     mod day5;
     mod day6;
     mod day7;
+    mod day8;
 }
 
 aoc_lib! { year = 2022 }