Finished aoc day 15 part 1

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2023-01-10 17:58:28 +01:00
parent 826bdd6db3
commit a72207c754
5 changed files with 186 additions and 0 deletions

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advent_of_code/2022/15/Cargo.lock generated Normal file
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# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
version = 3
[[package]]
name = "main"
version = "0.1.0"
dependencies = [
"nom",
]
[[package]]
name = "memchr"
version = "2.5.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
[[package]]
name = "minimal-lexical"
version = "0.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
[[package]]
name = "nom"
version = "7.1.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e5507769c4919c998e69e49c839d9dc6e693ede4cc4290d6ad8b41d4f09c548c"
dependencies = [
"memchr",
"minimal-lexical",
]

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[package]
name = "main"
version = "0.1.0"
edition = "2021"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
nom = "7.1.2"

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Sensor at x=1943362, y=12808: closest beacon is at x=1861152, y=-42022
Sensor at x=906633, y=3319637: closest beacon is at x=2096195, y=3402757
Sensor at x=2358896, y=2158796: closest beacon is at x=2331052, y=2934800
Sensor at x=1787606, y=3963631: closest beacon is at x=2096195, y=3402757
Sensor at x=2282542, y=3116014: closest beacon is at x=2331052, y=2934800
Sensor at x=173912, y=1873897: closest beacon is at x=429790, y=2000000
Sensor at x=3391153, y=3437167: closest beacon is at x=3720655, y=3880705
Sensor at x=3834843, y=2463103: closest beacon is at x=2971569, y=2563051
Sensor at x=3917316, y=3981011: closest beacon is at x=3720655, y=3880705
Sensor at x=1466100, y=1389028: closest beacon is at x=429790, y=2000000
Sensor at x=226600, y=3967233: closest beacon is at x=85598, y=4102832
Sensor at x=1757926, y=2834180: closest beacon is at x=2331052, y=2934800
Sensor at x=2176953, y=3240563: closest beacon is at x=2096195, y=3402757
Sensor at x=2883909, y=2533883: closest beacon is at x=2971569, y=2563051
Sensor at x=376161, y=2533578: closest beacon is at x=429790, y=2000000
Sensor at x=3015271, y=3913673: closest beacon is at x=3720655, y=3880705
Sensor at x=490678, y=388548: closest beacon is at x=429790, y=2000000
Sensor at x=2725765, y=2852933: closest beacon is at x=2331052, y=2934800
Sensor at x=86373, y=2839828: closest beacon is at x=429790, y=2000000
Sensor at x=1802070, y=14830: closest beacon is at x=1861152, y=-42022
Sensor at x=19628, y=1589839: closest beacon is at x=429790, y=2000000
Sensor at x=2713787, y=3381887: closest beacon is at x=2096195, y=3402757
Sensor at x=2148471, y=3729393: closest beacon is at x=2096195, y=3402757
Sensor at x=3999318, y=3263346: closest beacon is at x=3720655, y=3880705
Sensor at x=575700, y=1390576: closest beacon is at x=429790, y=2000000
Sensor at x=273266, y=2050976: closest beacon is at x=429790, y=2000000
Sensor at x=3008012, y=993590: closest beacon is at x=2971569, y=2563051
Sensor at x=3306379, y=2782128: closest beacon is at x=2971569, y=2563051
Sensor at x=44975, y=3820788: closest beacon is at x=85598, y=4102832
Sensor at x=2941700, y=2536797: closest beacon is at x=2971569, y=2563051
Sensor at x=2040164, y=102115: closest beacon is at x=1861152, y=-42022
Sensor at x=3928008, y=3692684: closest beacon is at x=3720655, y=3880705
Sensor at x=3905950, y=222812: closest beacon is at x=4759853, y=-796703

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use std::{collections::HashSet, hash::Hash};
use nom::{
IResult,
character::complete::{self,multispace1},
multi::separated_list1,
sequence::{preceded, separated_pair}, bytes::streaming::tag,
};
fn parse_input(input: &str) -> IResult<&str, Vec<((i32, i32), (i32, i32))>> {
let (input, coords) = separated_list1(
multispace1,
preceded(
tag("Sensor at x="),
separated_pair(
separated_pair(
complete::i32,
tag(", y="),
complete::i32,
),
tag(": closest beacon is at x="),
separated_pair(
complete::i32,
tag(", y="),
complete::i32,
))
)
)(input)?;
Ok((input, coords))
}
fn manhattan_dist(a: (i32, i32), b: (i32, i32)) -> i32 {
return (a.0 - b.0).abs() + (a.1 - b.1).abs();
}
fn fill_map(beacon_map: &mut HashSet<(i32, i32)>, sensor_coord: (i32, i32), beacon_coord: (i32, i32)) {
let dist = manhattan_dist(sensor_coord, beacon_coord);
let (sx, sy) = sensor_coord;
for i in 0..=dist {
for j in 0..=i {
beacon_map.insert((sx + i, sy + j));
beacon_map.insert((sx - i, sy + j));
beacon_map.insert((sx + i, sy - j));
beacon_map.insert((sx - i, sy - j));
}
}
}
fn fill_line(beacon_line: &mut HashSet<i32>, sensor_coord: (i32, i32), beacon_coord: (i32, i32), test_line: i32) {
let dist = manhattan_dist(sensor_coord, beacon_coord);
let (sx, sy) = sensor_coord;
let cross_section_len = dist - (test_line - sy).abs();
if cross_section_len >= 0 {
for i in 0..=cross_section_len {
beacon_line.insert(sx + i);
beacon_line.insert(sx - i);
}
}
}
fn main() {
let test_y = 2000000;
let input_text = include_str!("../input.txt");
let (_rest, coord_list) = parse_input(input_text).unwrap();
// Testing the parsing
// for ((sx, sy), (bx, by)) in coord_list {
// println!("Sensor at x={sx}, y={sy}: closest beacon is at x={bx}, y={by}");
// }
// Naive method
// let mut beacon_map = HashSet::new();
// for (sensor, beacon) in coord_list {
// fill_map(&mut beacon_map, sensor, beacon);
// }
// let positions = beacon_map.into_iter().filter(|(_, y)| *y == test_y).count();
// println!("Number of positions with y={test_y}: {positions}");
// A slightly less naive approach
let mut beacon_line = HashSet::new();
for (sensor, beacon) in coord_list {
fill_line(&mut beacon_line, sensor, beacon, test_y);
}
println!("Number of positions with y={test_y}: {}", beacon_line.len() - 1);
}

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Sensor at x=2, y=18: closest beacon is at x=-2, y=15
Sensor at x=9, y=16: closest beacon is at x=10, y=16
Sensor at x=13, y=2: closest beacon is at x=15, y=3
Sensor at x=12, y=14: closest beacon is at x=10, y=16
Sensor at x=10, y=20: closest beacon is at x=10, y=16
Sensor at x=14, y=17: closest beacon is at x=10, y=16
Sensor at x=8, y=7: closest beacon is at x=2, y=10
Sensor at x=2, y=0: closest beacon is at x=2, y=10
Sensor at x=0, y=11: closest beacon is at x=2, y=10
Sensor at x=20, y=14: closest beacon is at x=25, y=17
Sensor at x=17, y=20: closest beacon is at x=21, y=22
Sensor at x=16, y=7: closest beacon is at x=15, y=3
Sensor at x=14, y=3: closest beacon is at x=15, y=3
Sensor at x=20, y=1: closest beacon is at x=15, y=3