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Implement 2022 day 22 part 1

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Bert Peters
2022-12-23 09:03:26 +01:00
parent 06a61ab62c
commit a8752ad7a4
3 changed files with 397 additions and 2 deletions
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202
2022/inputs/22.txt Normal file
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183
2022/src/day22.rs
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@@ -1,9 +1,188 @@
use anyhow::Context;
use anyhow::Result;
use nom::branch::alt;
use nom::bytes::complete::tag;
use nom::bytes::complete::take_until;
use nom::character::complete::newline;
use nom::combinator::map;
use nom::combinator::value;
use nom::multi::many1;
use nom::sequence::separated_pair;
use nom::sequence::terminated;
use nom::IResult;
pub fn part1(_input: &[u8]) -> Result<String> {
anyhow::bail!("not implemented")
use crate::common::parse_input;
#[derive(Clone, Copy, Debug)]
enum Step {
Forward(u32),
Left,
Right,
}
#[derive(Clone, Copy)]
enum Direction {
Up = 3,
Down = 1,
Left = 2,
Right = 0,
}
impl Direction {
fn turn_left(self) -> Self {
match self {
Direction::Up => Direction::Left,
Direction::Down => Direction::Right,
Direction::Left => Direction::Down,
Direction::Right => Direction::Up,
}
}
fn turn_right(self) -> Self {
match self {
Direction::Up => Direction::Right,
Direction::Down => Direction::Left,
Direction::Left => Direction::Up,
Direction::Right => Direction::Down,
}
}
}
fn parse_map(input: &[u8]) -> IResult<&[u8], (Vec<&[u8]>, Vec<Step>)> {
separated_pair(
map(take_until("\n\n"), |map: &[u8]| {
map.split(|&b| b == b'\n').collect()
}),
tag("\n\n"),
terminated(
many1(alt((
map(nom::character::complete::u32, Step::Forward),
value(Step::Right, tag("R")),
value(Step::Left, tag("L")),
))),
newline,
),
)(input)
}
pub fn part1(input: &[u8]) -> Result<String> {
let (map, steps) = parse_input(input, parse_map)?;
let mut dir = Direction::Right;
let mut y = 0;
let mut x = map[y]
.iter()
.position(|&b| b == b'.')
.context("Could not find starting position")?;
for step in steps {
match step {
Step::Forward(amount) => match dir {
Direction::Up => {
for _ in 0..amount {
if y == 0 || map[y - 1].get(x).map(|&b| b == b' ').unwrap_or(true) {
let new_y = map
.iter()
.rposition(|line| {
line.get(x)
.map(|&b| b == b'.' || b == b'#')
.unwrap_or(false)
})
.unwrap();
if map[new_y][x] == b'#' {
break;
} else {
y = new_y;
}
} else if map[y - 1][x] == b'#' {
break;
} else {
y -= 1;
}
}
}
Direction::Down => {
for _ in 0..amount {
if y + 1 >= map.len()
|| map[y + 1].get(x).map(|&b| b == b' ').unwrap_or(true)
{
let new_y = map
.iter()
.position(|line| {
line.get(x)
.map(|&b| b == b'.' || b == b'#')
.unwrap_or(false)
})
.unwrap();
if map[new_y][x] == b'#' {
break;
} else {
y = new_y;
}
} else if map[y + 1][x] == b'#' {
break;
} else {
y += 1;
}
}
}
Direction::Left => {
for _ in 0..amount {
if x == 0 || map[y][x - 1] == b' ' {
let new_x = map[y]
.iter()
.rposition(|&b| b == b'.' || b == b'#')
.unwrap();
if map[y][new_x] == b'.' {
x = new_x;
} else {
break;
}
} else if map[y][x - 1] == b'#' {
break;
} else {
x -= 1;
}
}
}
Direction::Right => {
for _ in 0..amount {
if x + 1 >= map[y].len() || map[y][x + 1] == b' ' {
let new_x =
map[y].iter().position(|&b| b == b'.' || b == b'#').unwrap();
if map[y][new_x] == b'.' {
x = new_x;
} else {
break;
}
} else if map[y][x + 1] == b'#' {
break;
} else {
x += 1;
}
}
}
},
Step::Left => dir = dir.turn_left(),
Step::Right => dir = dir.turn_right(),
}
}
Ok((1000 * (y + 1) + 4 * (x + 1) + dir as usize).to_string())
}
pub fn part2(_input: &[u8]) -> Result<String> {
anyhow::bail!("not implemented")
}
#[cfg(test)]
mod tests {
use super::*;
const SAMPLE: &[u8] = include_bytes!("samples/22.txt");
#[test]
fn sample_part1() {
assert_eq!(part1(SAMPLE).unwrap(), "6032");
}
}

14
2022/src/samples/22.txt Normal file
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@@ -0,0 +1,14 @@
...#
.#..
#...
....
...#.......#
........#...
..#....#....
..........#.
...#....
.....#..
.#......
......#.
10R5L5R10L4R5L5