2019: day12: part 1

This commit is contained in:
Antoine Martin 2019-12-12 15:10:47 +01:00
parent 3ea1ca4ec5
commit f0a9da6065
5 changed files with 204 additions and 0 deletions

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@ -11,6 +11,7 @@ use aoc2019::day08;
use aoc2019::day09;
use aoc2019::day10;
use aoc2019::day11;
use aoc2019::day12;
fn aoc2019_all(c: &mut Criterion) {
c.bench_function("day01", |b| b.iter(|| day01::run().unwrap()));
@ -24,6 +25,7 @@ fn aoc2019_all(c: &mut Criterion) {
c.bench_function("day09", |b| b.iter(|| day09::run().unwrap()));
c.bench_function("day10", |b| b.iter(|| day10::run().unwrap()));
c.bench_function("day11", |b| b.iter(|| day11::run().unwrap()));
c.bench_function("day12", |b| b.iter(|| day12::run().unwrap()));
}
criterion_group! {

4
aoc2019/input/day12.txt Normal file
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@ -0,0 +1,4 @@
<x=-6, y=2, z=-9>
<x=12, y=-14, z=-4>
<x=9, y=5, z=-6>
<x=-1, y=-4, z=9>

195
aoc2019/src/day12.rs Normal file
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@ -0,0 +1,195 @@
use std::error::Error;
use std::fmt::Write;
use std::str::FromStr;
use aoc::err;
use aoc::Result;
const INPUT: &str = include_str!("../input/day12.txt");
pub fn run() -> Result<String> {
let mut res = String::with_capacity(128);
writeln!(res, "part 1: {}", part1(INPUT, 1000)?)?;
Ok(res)
}
fn generate_pairs_rec(res: &mut Vec<(usize, usize)>, tmp: &mut Vec<usize>, todo: usize, n: usize) {
if tmp.len() == 2 {
res.push((tmp[0], tmp[1]));
return;
}
for i in todo..n {
tmp.push(i);
generate_pairs_rec(res, tmp, i + 1, n);
tmp.pop();
}
}
fn generate_pairs(n: usize) -> Vec<(usize, usize)> {
let mut res = Vec::new();
let mut tmp = Vec::new();
generate_pairs_rec(&mut res, &mut tmp, 0, n);
res
}
fn part1(input: &str, steps: usize) -> Result<u64> {
let mut planets = input
.lines()
.map(|l| l.parse())
.collect::<Result<Vec<Planet>>>()?;
let pairs = generate_pairs(planets.len());
for _ in 0..steps {
// update velocity
for pair in pairs.iter().copied() {
let (begin, end) = planets.split_at_mut(pair.1);
let first = &mut begin[pair.0];
let second = &mut end[0];
if first.position.x > second.position.x {
first.velocity.x -= 1;
second.velocity.x += 1;
} else if first.position.x < second.position.x {
first.velocity.x += 1;
second.velocity.x -= 1;
}
if first.position.y > second.position.y {
first.velocity.y -= 1;
second.velocity.y += 1;
} else if first.position.y < second.position.y {
first.velocity.y += 1;
second.velocity.y -= 1;
}
if first.position.z > second.position.z {
first.velocity.z -= 1;
second.velocity.z += 1;
} else if first.position.z < second.position.z {
first.velocity.z += 1;
second.velocity.z -= 1;
}
}
// update position
for planet in planets.iter_mut() {
planet.update_pos();
}
}
Ok(planets.iter().map(|p| p.total_energy()).sum())
}
struct Vec3 {
x: i64,
y: i64,
z: i64,
}
struct Planet {
position: Vec3,
velocity: Vec3,
}
impl Planet {
fn new(position: Vec3) -> Self {
Planet {
position,
velocity: Vec3 { x: 0, y: 0, z: 0 },
}
}
fn update_pos(&mut self) {
self.position.x += self.velocity.x;
self.position.y += self.velocity.y;
self.position.z += self.velocity.z;
}
fn potential_energy(&self) -> u64 {
let pos = &self.position;
pos.x.abs() as u64 + pos.y.abs() as u64 + pos.z.abs() as u64
}
fn kinetic_energy(&self) -> u64 {
let vel = &self.velocity;
vel.x.abs() as u64 + vel.y.abs() as u64 + vel.z.abs() as u64
}
fn total_energy(&self) -> u64 {
self.kinetic_energy() * self.potential_energy()
}
}
impl FromStr for Planet {
type Err = Box<dyn Error>;
fn from_str(s: &str) -> Result<Self> {
let x_equals = s
.find("x=")
.ok_or_else(|| err!("couldn't find x value for planet: {}", s))?;
let comma = s
.find(',')
.ok_or_else(|| err!("couldn't find comma after x value: {}", s))?;
let x = s[(x_equals + 2)..comma].parse()?;
let s = &s[(comma + 1)..];
let y_equals = s
.find("y=")
.ok_or_else(|| err!("couldn't find y value for planet: {}", s))?;
let comma = s
.find(',')
.ok_or_else(|| err!("couldn't find comma after y value: {}", s))?;
let y = s[(y_equals + 2)..comma].parse()?;
let s = &s[(comma + 1)..];
let z_equals = s
.find("z=")
.ok_or_else(|| err!("couldn't find z value for planet: {}", s))?;
let bracket = s
.find('>')
.ok_or_else(|| err!("couldn't find bracket after z value: {}", s))?;
let z = s[(z_equals + 2)..bracket].parse()?;
Ok(Planet::new(Vec3 { x, y, z }))
}
}
#[cfg(test)]
mod tests {
use super::*;
const PROVIDED1: &str = "<x=-1, y=0, z=2>
<x=2, y=-10, z=-7>
<x=4, y=-8, z=8>
<x=3, y=5, z=-1>
";
const PROVIDED2: &str = "<x=-8, y=-10, z=0>
<x=5, y=5, z=10>
<x=2, y=-7, z=3>
<x=9, y=-8, z=-3>
";
#[test]
fn part1_provided() {
assert_eq!(part1(PROVIDED1, 10).unwrap(), 179);
assert_eq!(part1(PROVIDED2, 100).unwrap(), 1940);
}
#[test]
fn part1_real() {
assert_eq!(part1(INPUT, 1000).unwrap(), 14907);
}
}

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@ -11,3 +11,4 @@ pub mod day08;
pub mod day09;
pub mod day10;
pub mod day11;
pub mod day12;

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@ -12,6 +12,7 @@ use aoc2019::day08;
use aoc2019::day09;
use aoc2019::day10;
use aoc2019::day11;
use aoc2019::day12;
fn main() -> Result<()> {
let days: &[DayFunc] = &[
@ -26,6 +27,7 @@ fn main() -> Result<()> {
day09::run,
day10::run,
day11::run,
day12::run,
];
aoc::run(days)