year2016/
day02.rs

1use utils::prelude::*;
2
3/// Finding keypad codes.
4#[derive(Clone, Debug)]
5pub struct Day02<'a> {
6    input: &'a str,
7}
8
9impl<'a> Day02<'a> {
10    pub fn new(input: &'a str, _: InputType) -> Result<Self, InputError> {
11        if let Some(b) = input
12            .bytes()
13            .find(|b| !matches!(b, b'U' | b'D' | b'L' | b'R' | b'\n'))
14        {
15            return Err(InputError::new(
16                input,
17                b as char,
18                "expected U, D, L, R or newline",
19            ));
20        }
21
22        Ok(Self { input })
23    }
24
25    #[must_use]
26    pub fn part1(&self) -> String {
27        let mut num = 5;
28        let mut result = String::new();
29
30        for line in self.input.lines() {
31            for c in line.bytes() {
32                num = match (c, num) {
33                    (b'U', 4..=9) => num - 3,
34                    (b'D', 1..=6) => num + 3,
35                    (b'L', 2..=3 | 5..=6 | 8..=9) => num - 1,
36                    (b'R', 1..=2 | 4..=5 | 7..=8) => num + 1,
37                    (_, _) => num,
38                };
39            }
40            result.push((b'0' + num) as char);
41        }
42
43        result
44    }
45
46    #[must_use]
47    pub fn part2(&self) -> String {
48        let mut num = 5;
49        let mut result = String::new();
50
51        for line in self.input.lines() {
52            for c in line.bytes() {
53                num = match (c, num) {
54                    (b'U', 3) => 1,
55                    (b'U', 6..=8 | 10..=12) => num - 4,
56                    (b'U', 13) => 11,
57                    (b'D', 1) => 3,
58                    (b'D', 2..=4 | 6..=8) => num + 4,
59                    (b'D', 11) => 13,
60                    (b'L', 3..=4 | 6..=9 | 11..=12) => num - 1,
61                    (b'R', 2..=3 | 5..=8 | 10..=11) => num + 1,
62                    (_, _) => num,
63                };
64            }
65            result.push((if num >= 10 { b'A' - 10 } else { b'0' } + num) as char);
66        }
67
68        result
69    }
70}
71
72examples!(Day02<'_> -> (&'static str, &'static str) [
73    {input: "ULL\nRRDDD\nLURDL\nUUUUD", part1: "1985", part2: "5DB3"},
74]);
year2016/day02.rs

year2016/
day02.rs
