155 lines
4.1 KiB
Rust
155 lines
4.1 KiB
Rust
use aoc_runner_derive::{aoc, aoc_generator};
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#[derive(Debug)]
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pub enum Direction {
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North,
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East,
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South,
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West,
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}
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impl Direction {
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fn from_int(n: i64) -> Self {
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match n % 4 {
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0 => Self::East,
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1 => Self::South,
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2 => Self::West,
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3 => Self::North,
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_ => unreachable!(),
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}
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}
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}
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#[derive(Debug)]
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pub enum Command {
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Direction(Direction, i64),
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Left(i64),
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Right(i64),
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Forward(i64),
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}
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#[derive(Debug)]
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pub struct Ship {
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rot: i64,
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pos: (i64, i64),
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wp: (i64, i64),
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}
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impl Ship {
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fn new() -> Self {
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Self {
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rot: 0,
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pos: (0, 0),
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wp: (10, 1),
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}
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}
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fn facing(&self) -> Direction {
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Direction::from_int(self.rot)
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}
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fn cmd_p1(&mut self, cmd: &Command) {
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match cmd {
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Command::Direction(Direction::North, n) => {
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self.pos.1 += n;
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}
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Command::Direction(Direction::South, n) => {
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self.pos.1 -= n;
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}
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Command::Direction(Direction::East, n) => {
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self.pos.0 += n;
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}
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Command::Direction(Direction::West, n) => {
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self.pos.0 -= n;
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}
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Command::Left(n) => {
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self.rot -= n;
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}
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Command::Right(n) => {
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self.rot += n;
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}
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Command::Forward(n) => self.cmd_p1(&Command::Direction(self.facing(), *n)),
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}
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}
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fn cmd_p2(&mut self, cmd: &Command) {
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match cmd {
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Command::Direction(Direction::North, n) => {
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self.wp.1 += n;
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}
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Command::Direction(Direction::South, n) => {
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self.wp.1 -= n;
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}
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Command::Direction(Direction::East, n) => {
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self.wp.0 += n;
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}
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Command::Direction(Direction::West, n) => {
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self.wp.0 -= n;
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}
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Command::Right(n) => {
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let wp = self.wp;
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self.wp = match n % 4 {
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0 => wp,
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1 => (wp.1, -wp.0),
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2 => (-wp.0, -wp.1),
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3 => (-wp.1, wp.0),
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_ => unreachable!(),
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};
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}
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Command::Left(n) => {
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let wp = self.wp;
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self.wp = match n % 4 {
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0 => wp,
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1 => (-wp.1, wp.0),
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2 => (-wp.0, -wp.1),
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3 => (wp.1, -wp.0),
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_ => unreachable!(),
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};
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}
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Command::Forward(n) => {
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self.pos.0 += self.wp.0 * n;
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self.pos.1 += self.wp.1 * n;
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}
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}
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}
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}
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#[aoc_generator(day12)]
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pub fn input_generator(input: &str) -> Vec<Command> {
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input
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.lines()
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.map(|l| {
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let mut chars = l.chars();
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let cmd = chars.next().unwrap();
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let num = chars.collect::<String>().parse().unwrap();
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match cmd {
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'N' => Command::Direction(Direction::North, num),
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'S' => Command::Direction(Direction::South, num),
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'E' => Command::Direction(Direction::East, num),
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'W' => Command::Direction(Direction::West, num),
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'L' if num % 90 == 0 => Command::Left((num / 90) % 4),
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'R' if num % 90 == 0 => Command::Right((num / 90) % 4),
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'F' => Command::Forward(num),
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_ => panic!("Invalid command: {}", l),
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}
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})
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.collect::<Vec<Command>>()
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}
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#[aoc(day12, part1)]
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pub fn solve_part1(input: &Vec<Command>) -> usize {
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let mut ship = Ship::new();
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for cmd in input {
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ship.cmd_p1(cmd);
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}
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return (ship.pos.0.abs() as usize) + (ship.pos.1.abs() as usize);
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}
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#[aoc(day12, part2)]
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pub fn solve_part2(input: &Vec<Command>) -> usize {
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let mut ship = Ship::new();
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for cmd in input {
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ship.cmd_p2(cmd);
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}
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return (ship.pos.0.abs() as usize) + (ship.pos.1.abs() as usize);
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}
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