136 lines
3.1 KiB
Rust
136 lines
3.1 KiB
Rust
use std::str::FromStr;
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use aoc_runner_derive::{aoc, aoc_generator};
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use yap::{IntoTokens, Tokens};
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use crate::parsing::parse_number;
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#[aoc_generator(day2)]
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pub fn parse_movements(input: &str) -> Vec<Movement> {
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input
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.split('\n')
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.map(|input| input.parse().unwrap())
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.collect()
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}
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#[aoc(day2, part1)]
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pub fn part1(input: &[Movement]) -> isize {
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NaiveState::default().movements(input)
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}
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#[aoc(day2, part2)]
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pub fn part2(input: &[Movement]) -> isize {
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CorrectState::default().movements(input)
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}
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pub trait State {
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fn movement(&mut self, movement: &Movement);
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fn depth(&self) -> isize;
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fn horizontal_pos(&self) -> isize;
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fn result(&self) -> isize {
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self.depth() * self.horizontal_pos()
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}
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fn movements(&mut self, moves: &[Movement]) -> isize {
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for movement in moves {
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self.movement(movement);
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}
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self.result()
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}
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}
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#[derive(Default)]
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pub struct CorrectState {
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horizontal_pos: isize,
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depth: isize,
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aim: isize,
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}
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impl State for CorrectState {
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fn movement(&mut self, movement: &Movement) {
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match movement {
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Movement::Forward(units) => {
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self.horizontal_pos += units;
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self.depth += units * self.aim;
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}
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Movement::Down(units) => self.aim += units,
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Movement::Up(units) => self.aim -= units,
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}
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}
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fn depth(&self) -> isize {
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self.depth
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}
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fn horizontal_pos(&self) -> isize {
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self.horizontal_pos
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}
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}
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#[derive(Default)]
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pub struct NaiveState {
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horizontal_pos: isize,
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depth: isize,
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}
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impl State for NaiveState {
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fn movement(&mut self, movement: &Movement) {
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match movement {
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Movement::Forward(units) => self.horizontal_pos += units,
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Movement::Down(units) => self.depth += units,
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Movement::Up(units) => self.depth -= units,
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}
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}
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fn depth(&self) -> isize {
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self.depth
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}
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fn horizontal_pos(&self) -> isize {
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self.horizontal_pos
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}
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}
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pub enum Movement {
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Forward(isize),
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Down(isize),
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Up(isize),
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}
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#[allow(clippy::unnecessary_mut_passed)]
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impl FromStr for Movement {
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type Err = ();
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fn from_str(s: &str) -> Result<Self, Self::Err> {
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let mut tokens = s.into_tokens();
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yap::one_of!(ts from &mut tokens;
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ts.tokens("forward ".chars()).then(|| parse_number(ts).map(Movement::Forward)).flatten(),
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ts.tokens("down ".chars()).then(|| parse_number(ts).map(Movement::Down)).flatten(),
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ts.tokens("up ".chars()).then(|| parse_number(ts).map(Movement::Up)).flatten(),
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)
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.ok_or(())
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}
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}
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#[cfg(test)]
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mod tests {
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const EXAMPLE_INPUT: &str = "forward 5
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down 5
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forward 8
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up 3
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down 8
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forward 2";
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#[test]
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fn part1_example() {
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let input = super::parse_movements(EXAMPLE_INPUT);
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let result = super::part1(&input);
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assert_eq!(result, 150);
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}
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#[test]
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fn part2_example() {
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let input = super::parse_movements(EXAMPLE_INPUT);
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let result = super::part2(&input);
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assert_eq!(result, 900);
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}
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}
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