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
|
static DAY: u8 = 18;
fn main() {
let input = advent::read_lines(DAY);
println!("{DAY}a: {}", surface_area(&input));
println!("{DAY}b: {}", 0);
}
struct Cube {
x: i32,
y: i32,
z: i32,
}
impl Cube {
fn new(input: &str) -> Cube {
let mut coords = input.split(',');
let x = coords.next().unwrap().parse().unwrap();
let y = coords.next().unwrap().parse().unwrap();
let z = coords.next().unwrap().parse().unwrap();
Cube { x, y, z }
}
fn unconnected_surfaces(&self, cubes: &[Cube]) -> usize {
let neighbors = [
(self.x + 1, self.y, self.z),
(self.x - 1, self.y, self.z),
(self.x, self.y + 1, self.z),
(self.x, self.y - 1, self.z),
(self.x, self.y, self.z + 1),
(self.x, self.y, self.z - 1),
];
6 - cubes.iter()
.filter(|c| neighbors.contains(&(c.x, c.y, c.z)))
.count()
}
}
fn surface_area(input: &[String]) -> usize {
let cubes = input.iter()
.map(|x| Cube::new(x))
.collect::<Vec<_>>();
cubes.iter()
.map(|c| c.unconnected_surfaces(&cubes))
.sum()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
let input = [
"2,2,2",
"1,2,2",
"3,2,2",
"2,1,2",
"2,3,2",
"2,2,1",
"2,2,3",
"2,2,4",
"2,2,6",
"1,2,5",
"3,2,5",
"2,1,5",
"2,3,5",
].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
assert_eq!(surface_area(&input), 64);
}
}
|
