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day(08): address DRY

Signed-off-by: Matej Focko <mfocko@redhat.com>
This commit is contained in:
Matej Focko 2022-12-08 12:50:14 +01:00
parent e419087f1c
commit 7b364e35a3
Signed by: mfocko
GPG key ID: 7C47D46246790496

View file

@ -10,44 +10,41 @@ use tracing_subscriber::EnvFilter;
type Input = Vec<Vec<i8>>; type Input = Vec<Vec<i8>>;
type Output = usize; type Output = usize;
type Position = Vector2D<usize>;
type Visited = BTreeSet<Position>;
fn count_in(trees: &Input, counted: &mut BTreeSet<(usize, usize)>, swap: bool) {
fn folder(
trees: &Input,
counted: &mut BTreeSet<(usize, usize)>,
mut x: usize,
mut y: usize,
swap: bool,
tallest: i8,
) -> i8 {
if swap {
(x, y) = (y, x);
}
if trees[y][x] > tallest {
counted.insert((x, y));
}
max(tallest, trees[y][x])
}
(0..trees.len()).for_each(|y| {
(0..trees[y].len()).fold(-1, |tallest, x| folder(trees, counted, x, y, swap, tallest));
(0..trees[y].len()).rfold(-1, |tallest, x| folder(trees, counted, x, y, swap, tallest));
})
}
fn count_in_rows(trees: &Input, counted: &mut BTreeSet<(usize, usize)>) { fn count_in_rows(trees: &Input, counted: &mut BTreeSet<(usize, usize)>) {
trees.iter().enumerate().for_each(|(y, row)| { count_in(trees, counted, false)
row.iter().enumerate().fold(-1, |tallest, (x, tree)| {
if *tree > tallest {
counted.insert((x, y));
}
max(*tree, tallest)
});
row.iter().enumerate().rfold(-1, |tallest, (x, tree)| {
if *tree > tallest {
counted.insert((x, y));
}
max(*tree, tallest)
});
});
} }
fn count_in_columns(trees: &Input, counted: &mut BTreeSet<(usize, usize)>) { fn count_in_columns(trees: &Input, counted: &mut BTreeSet<(usize, usize)>) {
(0..trees[0].len()).for_each(|x| { count_in(trees, counted, true)
(0..trees.len()).fold(-1, |tallest, y| {
if trees[y][x] > tallest {
counted.insert((x, y));
}
max(tallest, trees[y][x])
});
(0..trees.len()).rev().fold(-1, |tallest, y| {
if trees[y][x] > tallest {
counted.insert((x, y));
}
max(tallest, trees[y][x])
});
});
} }
fn part_1(input: &Input) -> Output { fn part_1(input: &Input) -> Output {
@ -63,10 +60,7 @@ fn in_range(trees: &Input, x: i32, y: i32) -> bool {
y >= 0 && y < trees.len() as i32 && x >= 0 && x < trees[y as usize].len() as i32 y >= 0 && y < trees.len() as i32 && x >= 0 && x < trees[y as usize].len() as i32
} }
fn compute_scenic_score(trees: &Input, x: i32, y: i32) -> usize { fn count_visible(trees: &Input, x: i32, y: i32, dx: i32, dy: i32) -> usize {
vec![(0, 1), (1, 0), (0, -1), (-1, 0)]
.iter()
.map(|&(dx, dy)| {
let max_height = trees[y as usize][x as usize]; let max_height = trees[y as usize][x as usize];
let mut d = 1; let mut d = 1;
@ -83,7 +77,12 @@ fn compute_scenic_score(trees: &Input, x: i32, y: i32) -> usize {
} }
visible as usize visible as usize
}) }
fn compute_scenic_score(trees: &Input, x: i32, y: i32) -> usize {
vec![(0, 1), (1, 0), (0, -1), (-1, 0)]
.iter()
.map(|&(dx, dy)| count_visible(trees, x, y, dx, dy))
.product() .product()
} }