kageru/advent-of-code
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optimize 2023/03/2

This commit is contained in:
kageru 2023-12-03 15:18:21 +01:00
parent 77ff6daad8
commit 072c178cb8
1 changed files with 20 additions and 7 deletions
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27
2023/src/bin/day03.rs
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@ -11,17 +11,28 @@ use itertools::Itertools;
const DAY: usize = 3;
type Grid<'a> = Vec<&'a [u8]>;
type Parsed<'a> = (Grid<'a>, Vec<(usize, RangeInclusive<usize>)>);
type Parsed<'a> = (Grid<'a>, Vec<Vec<(usize, RangeInclusive<usize>)>>);
fn parse_input(raw: &str) -> Parsed {
let grid = raw.lines().map(|l| l.as_bytes()).collect_vec();
let number_positions = grid
.iter()
.enumerate()
.flat_map(|(x, l)| l.iter().enumerate().filter_map(move |(y, c)| c.is_ascii_digit().then_some((x, y..=y))))
.coalesce(
|(x1, y1), (x2, y2)| if y1.end() + 1 == *y2.start() { Ok((x1, *y1.start()..=*y2.end())) } else { Err(((x1, y1), (x2, y2))) },
)
.map(|(x, l)| {
l.iter()
.enumerate()
.filter_map(move |(y, c)| c.is_ascii_digit().then_some((x, y..=y)))
.coalesce(
|(x1, y1), (x2, y2)| {
if y1.end() + 1 == *y2.start() {
Ok((x1, *y1.start()..=*y2.end()))
} else {
Err(((x1, y1), (x2, y2)))
}
},
)
.collect_vec()
})
.collect_vec();
(grid, number_positions)
}
@ -33,6 +44,7 @@ fn parse_at(grid: &Grid, (x, ys): (usize, RangeInclusive<usize>)) -> usize {
fn part1((grid, number_positions): &Parsed) -> usize {
number_positions
.iter()
.flatten()
.cloned()
.filter_map(|(x, ys)| {
let start = Position2D::from([x, *ys.start()]);
@ -59,8 +71,9 @@ fn part2((grid, number_positions): &Parsed) -> usize {
.flat_map(|(x, ys)| ys.iter().enumerate().filter_map(move |(y, &b)| (b == b'*').then_some(Position2D::from([x, y]))))
.filter_map(|p| {
let neighbors = p.neighbors();
number_positions
number_positions[((p.0[0] - 1) as usize)..=((p.0[0] + 1) as usize)]
.iter()
.flatten()
.filter_map(|np| neighbors.iter().find_map(|&n| part_of(n, np).then(|| parse_at(grid, np.clone()))))
.collect_tuple()
})
@ -85,5 +98,5 @@ boilerplate! {
},
bench1 == 536202,
bench2 == 78272573,
bench_parse: |(g, ns): &Parsed| (g.len(), ns.len()) => (140, 1203),
bench_parse: |(g, ns): &Parsed| (g.len(), ns.len()) => (140, 140),
}