-
Notifications
You must be signed in to change notification settings - Fork 3
/
day_01.rs
95 lines (78 loc) · 1.95 KB
/
day_01.rs
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
use common::{Answer, Solution};
pub struct Day01;
const DIGITS: [&str; 9] = [
"one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
];
impl Solution for Day01 {
fn name(&self) -> &'static str {
"Trebuchet?!"
}
fn part_a(&self, input: &str) -> Answer {
let mut sum = 0;
for line in input.lines() {
let mut digits = line.chars().filter_map(|c| c.to_digit(10));
let first = digits.next().unwrap();
let last = digits.last().unwrap_or(first);
sum += first * 10 + last;
}
sum.into()
}
fn part_b(&self, input: &str) -> Answer {
let mut sum = 0;
for line in input.lines() {
let digits = digits(line);
sum += digits[0] * 10 + digits[1];
}
sum.into()
}
}
fn digits(i: &str) -> [u32; 2] {
let mut first = None;
let mut last = 0;
let mut digit = |c| {
first = first.or(Some(c));
last = c;
};
let chars = i.as_bytes();
for (i, c) in chars.iter().enumerate() {
if c.is_ascii_digit() {
digit((c - b'0') as u32);
} else {
for (j, d) in DIGITS.iter().enumerate() {
if chars[i..].starts_with(d.as_bytes()) {
digit(j as u32 + 1);
}
}
}
}
[first.unwrap(), last]
}
#[cfg(test)]
mod test {
use common::Solution;
use indoc::indoc;
use super::Day01;
const CASE_A: &str = indoc! {"
1abc2
pqr3stu8vwx
a1b2c3d4e5f
treb7uchet
"};
const CASE_B: &str = indoc! {"
two1nine
eightwothree
abcone2threexyz
xtwone3four
4nineeightseven2
zoneight234
7pqrstsixteen
"};
#[test]
fn part_a() {
assert_eq!(Day01.part_a(CASE_A), 142.into());
}
#[test]
fn part_b() {
assert_eq!(Day01.part_b(CASE_B), 281.into());
}
}