1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug, Default)]
enum Tile {
Open,
Wall,
#[default]
Noop,
}
#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug)]
enum Step {
Forward(usize),
Left,
Right,
}
#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug)]
enum Direction {
Right,
Down,
Left,
Up,
}
impl std::convert::From<Direction> for usize {
fn from(direction: Direction) -> Self {
match direction {
Direction::Right => 0,
Direction::Down => 1,
Direction::Left => 2,
Direction::Up => 3,
}
}
}
impl Direction {
fn left(&self) -> Self {
match self {
Direction::Right => Direction::Up,
Direction::Down => Direction::Right,
Direction::Left => Direction::Down,
Direction::Up => Direction::Left,
}
}
fn right(&self) -> Self {
match self {
Direction::Right => Direction::Down,
Direction::Down => Direction::Left,
Direction::Left => Direction::Up,
Direction::Up => Direction::Right,
}
}
}
#[derive(Debug)]
pub struct Map {
grid: Grid<Tile>,
path: Vec<Step>,
}
impl Map {
fn step(&self, pos: (Row, Col), facing: Direction) -> (Row, Col) {
let (row_diff, col_diff, sub) = match facing {
Direction::Right => (0, 1, false),
Direction::Down => (1, 0, false),
Direction::Left => (0, 1, true),
Direction::Up => (1, 0, true),
};
let rows = self.grid.rows().0;
let cols = self.grid.cols().0;
let mut new_pos = pos;
new_pos = (
if sub {
rows + new_pos.0 - row_diff
} else {
rows + new_pos.0 + row_diff
} % rows,
if sub {
cols + new_pos.1 - col_diff
} else {
cols + new_pos.1 + col_diff
} % cols,
);
while matches!(self.grid[new_pos.0][new_pos.1], Tile::Noop) {
new_pos = (
if sub {
rows + new_pos.0 - row_diff
} else {
rows + new_pos.0 + row_diff
} % rows,
if sub {
cols + new_pos.1 - col_diff
} else {
cols + new_pos.1 + col_diff
} % cols,
);
}
if matches!(self.grid[new_pos.0][new_pos.1], Tile::Wall) {
pos
} else {
new_pos
}
}
}
pub fn parse(fh: File) -> Result<Map> {
let mut lines = parse::raw_lines(fh);
let grid = parse::grid(parse::chunk(&mut lines), |c, _, _| match c {
b' ' => Tile::Noop,
b'.' => Tile::Open,
b'#' => Tile::Wall,
_ => panic!("invalid map tile {}", c),
});
let path_str = lines.next().unwrap();
let mut path_str = &path_str[..];
let mut path = vec![];
while let Some(first) = path_str.chars().next() {
match first {
'R' => {
path.push(Step::Right);
path_str = &path_str[1..];
}
'L' => {
path.push(Step::Left);
path_str = &path_str[1..];
}
'0'..='9' => {
let prefix_len = path_str
.chars()
.take_while(|c| ('0'..='9').contains(c))
.count();
path.push(Step::Forward(
path_str[0..prefix_len].parse().unwrap(),
));
path_str = &path_str[prefix_len..];
}
_ => panic!("invalid path char {}", first),
}
}
Ok(Map { grid, path })
}
pub fn part1(map: Map) -> Result<usize> {
let mut pos = (Row(0), Col(0));
let mut facing = Direction::Right;
for step in &map.path {
match step {
Step::Left => facing = facing.left(),
Step::Right => facing = facing.right(),
Step::Forward(n) => {
for _ in 0..*n {
pos = map.step(pos, facing);
}
}
}
}
Ok((pos.0 .0 + 1) * 1000 + (pos.1 .0 + 1) * 4 + usize::from(facing))
}
pub fn part2(map: Map) -> Result<usize> {
todo!()
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2022, 22).unwrap()).unwrap()).unwrap(),
95358
);
// assert_eq!(
// part2(parse(parse::data(2022, 22).unwrap()).unwrap()).unwrap(),
// 0
// );
}
|
