kageru/advent-of-code
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clean up day 15

This commit is contained in:
kageru 2022-12-15 13:19:33 +01:00
parent 460d7c10a7
commit d2e5c13586
1 changed files with 17 additions and 31 deletions
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48
2022/src/bin/day15.rs
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@ -5,7 +5,7 @@ use aoc2022::{boilerplate, common::*};
use itertools::Itertools; use itertools::Itertools;
const DAY: usize = 15; const DAY: usize = 15;
type Parsed = Vec<((i64, i64), (i64, i64), u64)>; type Parsed = Vec<((i64, i64), u64)>;
fn parse_input(raw: &str) -> Parsed { fn parse_input(raw: &str) -> Parsed {
raw.lines() raw.lines()
@ -15,7 +15,7 @@ fn parse_input(raw: &str) -> Parsed {
.map(|s| s.parse().unwrap()) .map(|s| s.parse().unwrap())
}) })
.map(|[x1, y1, x2, y2]| ((x1, y1), (x2, y2))) .map(|[x1, y1, x2, y2]| ((x1, y1), (x2, y2)))
.map(|(t1, t2)| (t1, t2, manhattan(t1, t2))) .map(|(t1, t2)| (t1, manhattan(t1, t2)))
.collect() .collect()
} }
@ -23,48 +23,34 @@ fn manhattan((x1, y1): (i64, i64), (x2, y2): (i64, i64)) -> u64 {
x1.abs_diff(x2) + y1.abs_diff(y2) x1.abs_diff(x2) + y1.abs_diff(y2)
} }
fn part1(parsed: &Parsed, y: i64) -> usize { fn part1(parsed: &Parsed, y: i64) -> i64 {
let max_distance = *parsed.iter().map(|(_, _, d)| d).max().unwrap() + 1; let (&min_x, &max_x) = parsed.iter().map(|((x1, _), _)| x1).minmax().into_option().unwrap();
let (&min_x, &max_x) = parsed.iter().map(|((x1, _), _, _)| x1).minmax().into_option().unwrap(); let mut x = min_x - *parsed.iter().map(|(_, d)| d).max().unwrap() as i64;
let mut c = 0; let mut c = 0;
let mut nearest = None; while x <= max_x {
for x in (min_x - max_distance as i64)..=(max_x + max_distance as i64) { match parsed.iter().find(|(p, d)| manhattan(*p, (x, y)) <= *d) {
match nearest { Some(&((px, py), d)) => {
None => { let new_x = px + d as i64 - (py.abs_diff(y) as i64) + 1;
nearest = parsed.iter().find(|(p, _, d)| manhattan(*p, (x, y)) <= *d); c += new_x - x;
if nearest.is_some() { x = new_x;
c += 1;
}
} }
Some(&(p, _, d)) => { None => x += 1,
if manhattan(p, (x, y)) <= d { };
c += 1;
} else {
nearest = parsed.iter().find(|(p, _, d)| manhattan(*p, (x, y)) <= *d);
if nearest.is_some() {
c += 1;
}
}
}
}
} }
c - 1 // no idea why this is consistently off by 1 c - 1
} }
fn part2(parsed: &Parsed, bounds: i64) -> i64 { fn part2(parsed: &Parsed, bounds: i64) -> i64 {
for x in 0..=bounds { for x in 0..=bounds {
let mut y = 0; let mut y = 0;
while y <= bounds { while y <= bounds {
match parsed.iter().find(|(p, _, d)| manhattan(*p, (x, y)) <= *d) { match parsed.iter().find(|(p, d)| manhattan(*p, (x, y)) <= *d) {
Some(&((px, py), _, d)) => { Some(&((px, py), d)) => y = py + d as i64 - (px.abs_diff(x) as i64) + 1,
y = py + d as i64 - (px.abs_diff(x) as i64) + 1;
}
None => return x * 4_000_000 + y, None => return x * 4_000_000 + y,
}; };
} }
} }
panic!("Did not find an eligible spot") unreachable!("Did not find an eligible spot")
} }
boilerplate! { boilerplate! {