advent-of-code/2020/src/grid.rs

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use impl_ops::*;
use itertools::join;
use std::{collections::HashMap, fmt::Display, hash::BuildHasher, ops, ops::AddAssign};
#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy)]
pub struct Position2D {
pub x: i64,
pub y: i64,
}
#[derive(Clone, Copy, Debug)]
pub enum Direction {
Up,
Down,
Left,
Right,
}
pub const ALL_DIRECTIONS: [Direction; 4] = [Direction::Up, Direction::Down, Direction::Left, Direction::Right];
struct Boundaries {
x_min: i64,
x_max: i64,
y_min: i64,
y_max: i64,
}
#[rustfmt::skip]
fn get_boundaries(input: &[&Position2D]) -> Boundaries {
let x_min = input.iter().min_by_key(|k| k.x).map(|p| p.x).unwrap_or(0);
let x_max = input.iter().max_by_key(|k| k.x).map(|p| p.x).unwrap_or(0);
let y_min = input.iter().min_by_key(|k| k.y).map(|p| p.y).unwrap_or(0);
let y_max = input.iter().max_by_key(|k| k.y).map(|p| p.y).unwrap_or(0);
Boundaries { x_min, x_max, y_min, y_max }
}
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pub fn draw_ascii<T: Display + Default, S: BuildHasher>(coordinates: &HashMap<Position2D, T, S>) -> String {
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let b = get_boundaries(&coordinates.keys().collect::<Vec<_>>());
join(
(b.y_min..=b.y_max).rev().map(|y| {
(b.x_min..=b.x_max)
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.map(|x| coordinates.get(&(x, y).into()).unwrap_or(&T::default()).to_string())
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.collect::<String>()
}),
"\n",
)
}
impl Position2D {
pub fn neighbors(&self) -> [(Direction, Position2D); 4] {
[
(Direction::Up, *self + Direction::Up),
(Direction::Down, *self + Direction::Down),
(Direction::Right, *self + Direction::Right),
(Direction::Left, *self + Direction::Left),
]
}
pub fn moore(&self) -> [Position2D; 8] {
[
*self + Direction::Up + Direction::Left,
*self + Direction::Up,
*self + Direction::Up + Direction::Right,
*self + Direction::Left,
*self + Direction::Right,
*self + Direction::Down + Direction::Left,
*self + Direction::Down,
*self + Direction::Down + Direction::Right,
]
}
}
impl Direction {
pub fn turn(&mut self, turn_value: i64) {
*self += turn_value as i8;
}
}
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impl From<Direction> for Position2D {
fn from(d: Direction) -> Self {
match d {
Direction::Up => Position2D::from((0, 1)),
Direction::Right => Position2D::from((1, 0)),
Direction::Left => Position2D::from((-1, 0)),
Direction::Down => Position2D::from((0, -1)),
}
}
}
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impl_op!(+ |a: Direction, b: i8| -> Direction {
match b {
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-1 | 3 => match a {
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Direction::Up => Direction::Left,
Direction::Right => Direction::Up,
Direction::Down => Direction::Right,
Direction::Left => Direction::Down,
},
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1 | -3 => match a {
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Direction::Up => Direction::Right,
Direction::Right => Direction::Down,
Direction::Down => Direction::Left,
Direction::Left => Direction::Up,
},
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0 | 4 | -4 => a,
2 | -2 => match a {
Direction::Up => Direction::Down,
Direction::Right => Direction::Left,
Direction::Down => Direction::Up,
Direction::Left => Direction::Right,
},
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n => unreachable!(format!("Illegal turn value: {}", n)),
}
});
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impl_op!(+|a: Position2D, b: Position2D| -> Position2D {
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Position2D {
x: a.x + b.x,
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y: a.y + b.y
}
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});
impl_op!(-|a: Position2D, b: Position2D| -> Position2D {
Position2D {
x: a.x - b.x,
y: a.y - b.y,
}
});
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impl_op!(+|a: Position2D, b: Direction| -> Position2D {
a + Position2D::from(b)
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});
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impl_op!(-|a: Position2D, b: Direction| -> Position2D { a - Position2D::from(b) });
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impl_op!(*|a: Position2D, b: i64| -> Position2D { Position2D { x: a.x * b, y: a.y * b } });
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impl AddAssign<i8> for Direction {
fn add_assign(&mut self, rhs: i8) {
*self = *self + rhs;
}
}
impl AddAssign<Direction> for Position2D {
fn add_assign(&mut self, rhs: Direction) {
*self = *self + rhs;
}
}
impl AddAssign for Position2D {
fn add_assign(&mut self, rhs: Position2D) {
*self = *self + rhs;
}
}
impl From<(usize, usize)> for Position2D {
fn from(tuple: (usize, usize)) -> Position2D {
Position2D {
x: tuple.0 as i64,
y: tuple.1 as i64,
}
}
}
impl From<(i32, i32)> for Position2D {
fn from(tuple: (i32, i32)) -> Position2D {
Position2D {
x: tuple.0 as i64,
y: tuple.1 as i64,
}
}
}
impl From<(i64, i64)> for Position2D {
fn from(tuple: (i64, i64)) -> Position2D {
Position2D { x: tuple.0, y: tuple.1 }
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_add() {
assert_eq!(Position2D { x: 0, y: 2 } + Position2D { x: -1, y: 0 }, (-1, 2).into());
assert_eq!(Position2D { x: 0, y: -1 } + Direction::Up, (0, 0).into());
}
}