nove.dev
:)
factor out some of the generic spatial code
+4
-84
src/day4.rs
+4
-84
src/day4.rs
···
1
-
use itertools::Itertools;
1
+
use crate::spatial::*;
2
2
3
3
pub fn day4_part1(input: &str) -> String {
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let roll_locations = parse(input);
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-
removable_rolls(&roll_locations).len().to_string()
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+
removable_rolls(&roll_locations).count().to_string()
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6
}
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//fixed point algorithm go brrr
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pub fn day4_part2(input: &str) -> String {
···
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rolls_removed.to_string()
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}
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-
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-
fn removable_rolls(roll_locations: &[Vec<bool>]) -> Vec<Point> {
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+
fn removable_rolls(roll_locations: &[Vec<bool>]) -> impl Iterator<Item = Point> {
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all_coords(roll_locations[0].len(), roll_locations.len())
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.filter(|coords| roll_locations[coords.row][coords.col])
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.filter(|&coords| {
···
30
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.filter(|&&neighbour| neighbour)
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.count()
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< 4
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-
}).collect()
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+
})
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}
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fn parse(input: &str) -> Vec<Vec<bool>> {
···
39
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.map(|line| line.chars().map(|c| c == '@').collect())
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.collect()
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}
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-
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fn unparse(grid: &[Vec<bool>]) -> String {
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grid.iter()
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.map(|row| {
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row.iter()
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.map(|&is_roll| if is_roll { '@' } else { '.' })
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.collect::<String>()
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})
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.join("\n")
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}
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-
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#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
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struct Point {
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row: usize,
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col: usize,
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}
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-
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fn all_coords(width: usize, height: usize) -> impl Iterator<Item = Point> {
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(0..height)
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.cartesian_product(0..width)
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.map(|(row, col)| Point { row, col })
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}
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-
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/// North, East, South, West, Northeast, Southeast, Southwest, Northwest
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fn adjacent_including_diagonals<T: Copy + std::fmt::Debug>(
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-
grid: &[Vec<T>],
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coords: Point,
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) -> [Option<T>; 8] {
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-
[
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adjacent_cardinal(grid, coords),
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-
adjacent_ordinal(grid, coords),
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-
]
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.concat()
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.try_into()
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.unwrap()
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}
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-
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///Never Eat Shredded Wheat
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fn adjacent_cardinal<T: Copy>(grid: &[Vec<T>], coords: Point) -> [Option<T>; 4] {
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let mut retval = [const { None }; 4];
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let (row, col) = (coords.row, coords.col);
83
-
84
-
if row > 0 {
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retval[0] = Some(grid[row - 1][col]) //N
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-
}
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if col < grid[0].len() - 1 {
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retval[1] = Some(grid[row][col + 1]) //E
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}
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if row < grid.len() - 1 {
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retval[2] = Some(grid[row + 1][col]) //S
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}
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if col > 0 {
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retval[3] = Some(grid[row][col - 1]) //N
95
-
}
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-
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retval
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}
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-
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-
/// Never Eat Shredded Wheat, rotated 45 degrees clockwise
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/// AKA northeast, southeast, southwest, northwest
102
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fn adjacent_ordinal<T: Copy>(grid: &[Vec<T>], coords: Point) -> [Option<T>; 4] {
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let mut retval = [const { None }; 4];
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let (row, col) = (coords.row, coords.col);
105
-
106
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if row > 0 && col < grid[0].len() - 1 {
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retval[0] = Some(grid[row - 1][col + 1]) //NE
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}
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if row < grid.len() - 1 && col < grid[0].len() - 1 {
110
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retval[1] = Some(grid[row + 1][col + 1]) //SE
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-
}
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if row < grid.len() - 1 && col > 0 {
113
-
retval[2] = Some(grid[row + 1][col - 1]) //SW
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-
}
115
-
if row > 0 && col > 0 {
116
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retval[3] = Some(grid[row - 1][col - 1]) //NW
117
-
}
118
-
119
-
retval
120
-
}
+1
src/lib.rs
+1
src/lib.rs
+72
src/spatial.rs
+72
src/spatial.rs
···
1
+
use itertools::Itertools;
2
+
3
+
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
4
+
pub struct Point {
5
+
pub row: usize,
6
+
pub col: usize,
7
+
}
8
+
9
+
pub fn all_coords(width: usize, height: usize) -> impl Iterator<Item = Point> {
10
+
(0..height)
11
+
.cartesian_product(0..width)
12
+
.map(|(row, col)| Point { row, col })
13
+
}
14
+
15
+
/// North, East, South, West, Northeast, Southeast, Southwest, Northwest
16
+
/// Depends on `coords` being within bounds
17
+
pub fn adjacent_including_diagonals<T: Copy + std::fmt::Debug>(
18
+
grid: &[Vec<T>],
19
+
coords: Point,
20
+
) -> [Option<T>; 8] {
21
+
[
22
+
adjacent_cardinal(grid, coords),
23
+
adjacent_ordinal(grid, coords),
24
+
]
25
+
.concat()
26
+
.try_into()
27
+
.unwrap()
28
+
}
29
+
30
+
//could make these use .get() for safe out-of-bounds reads, i suppose
31
+
///Never Eat Shredded Wheat
32
+
fn adjacent_cardinal<T: Copy>(grid: &[Vec<T>], coords: Point) -> [Option<T>; 4] {
33
+
let mut retval = [const { None }; 4];
34
+
let (row, col) = (coords.row, coords.col);
35
+
36
+
if row > 0 {
37
+
retval[0] = Some(grid[row - 1][col]) //N
38
+
}
39
+
if col < grid[0].len() - 1 {
40
+
retval[1] = Some(grid[row][col + 1]) //E
41
+
}
42
+
if row < grid.len() - 1 {
43
+
retval[2] = Some(grid[row + 1][col]) //S
44
+
}
45
+
if col > 0 {
46
+
retval[3] = Some(grid[row][col - 1]) //N
47
+
}
48
+
49
+
retval
50
+
}
51
+
52
+
/// Never Eat Shredded Wheat, rotated 45 degrees clockwise
53
+
/// AKA northeast, southeast, southwest, northwest
54
+
fn adjacent_ordinal<T: Copy>(grid: &[Vec<T>], coords: Point) -> [Option<T>; 4] {
55
+
let mut retval = [const { None }; 4];
56
+
let (row, col) = (coords.row, coords.col);
57
+
58
+
if row > 0 && col < grid[0].len() - 1 {
59
+
retval[0] = Some(grid[row - 1][col + 1]) //NE
60
+
}
61
+
if row < grid.len() - 1 && col < grid[0].len() - 1 {
62
+
retval[1] = Some(grid[row + 1][col + 1]) //SE
63
+
}
64
+
if row < grid.len() - 1 && col > 0 {
65
+
retval[2] = Some(grid[row + 1][col - 1]) //SW
66
+
}
67
+
if row > 0 && col > 0 {
68
+
retval[3] = Some(grid[row - 1][col - 1]) //NW
69
+
}
70
+
71
+
retval
72
+
}