blob: 78224c42850c838245c57482e71588973d0bb923 (
plain) (
blame)
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
|
const INPUT_FILE: &str = "input";
#[derive(PartialEq, Clone, Copy)]
enum Direction {
Up,
Down,
Unknown,
}
use Direction::*;
fn is_safe(levels: &[u32]) -> bool {
let mut direction = Unknown;
for i in 0..levels.len() - 1 {
let [x, y] = levels[i..=i + 1] else {
unreachable!()
};
let (diff, d) = if x > y { (x - y, Down) } else { (y - x, Up) };
if let Unknown = direction {
direction = d;
}
if diff == 0 || diff > 3 || direction != d {
return false;
}
}
return true;
}
fn is_safe_with_dampener(levels: &[u32]) -> bool {
for i in 0..levels.len() {
let mut levels_without_i: Vec<u32> = levels.to_vec();
levels_without_i.remove(i);
if is_safe(&levels_without_i) {
return true;
}
}
return false;
}
fn main() {
let input = std::fs::read_to_string(INPUT_FILE).unwrap();
let mut total = 0;
for report in input.lines() {
let levels: Vec<u32> = report
.split_whitespace()
.map(|l| l.parse().unwrap())
.collect();
if is_safe(&levels) || is_safe_with_dampener(&levels) {
total += 1;
}
}
println!("Levels! {:?}", total);
}
|
