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use core::num; | ||
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use crate::util::{Day, Solution}; | ||
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pub struct Day1; | ||
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impl Day for Day1 { | ||
fn solve(input: &str) -> Solution { | ||
let (part1, part2) = input | ||
.lines() | ||
.take_while(|line| !line.is_empty()) | ||
.map(|line| (part1_line(&line), part2_line(line))) | ||
.reduce(|(p1, p2), (part1, part2)| (p1 + part1, p2 + part2)) | ||
.expect("Failed to solve"); | ||
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(part1, part2) | ||
} | ||
} | ||
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fn part1_line(line: &str) -> usize { | ||
let numbers: Vec<usize> = line | ||
.chars() | ||
.filter(|char| char.is_ascii_digit()) | ||
.map(|char| char.to_string().parse().expect("Expected a number")) | ||
.collect(); | ||
let first = numbers.first().unwrap_or(&0); | ||
let last = numbers.last().unwrap_or(&0); | ||
first * 10 + last | ||
} | ||
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fn part2_line(line: &str) -> usize { | ||
const WORD_NUMBERS: [&str; 9] = [ | ||
"one", "two", "three", "four", "five", "six", "seven", "eight", "nine", | ||
]; | ||
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fn of_two_option<F>(a: Option<usize>, b: Option<usize>, f: F) -> Option<usize> | ||
where | ||
F: Fn(usize, usize) -> usize, | ||
{ | ||
match (a, b) { | ||
(None, None) => None, | ||
(None, Some(i)) => Some(i), | ||
(Some(i), None) => Some(i), | ||
(Some(l), Some(r)) => Some(f(l, r)), | ||
} | ||
} | ||
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let res = WORD_NUMBERS | ||
.iter() | ||
.enumerate() | ||
.flat_map(|(index, &word)| { | ||
let number = index + 1; | ||
let (number_first, number_last) = { | ||
let number_string = &number.to_string(); | ||
(line.find(number_string), line.rfind(number_string)) | ||
}; | ||
let word_first = line.find(word); | ||
let word_last = line.rfind(word); | ||
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let min = of_two_option(number_first, word_first, usize::min).map(|idx| (idx, number)); | ||
let max = of_two_option(number_last, word_last, usize::max).map(|idx| (idx, number)); | ||
vec![min, max] | ||
}) | ||
.flatten() | ||
.collect::<Vec<_>>(); | ||
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let tens = res | ||
.iter() | ||
.min_by_key(|(idx, _num)| idx) | ||
.map(|(_, number)| number) | ||
.expect("Expected to find at least one number"); | ||
let ones = res | ||
.iter() | ||
.max_by_key(|(idx, _num)| idx) | ||
.map(|(_, number)| number) | ||
.expect("Expected to find at least one number"); | ||
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println!("In {line} we have ({tens}, {ones})"); | ||
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// 55336 too HIGH | ||
10 * tens + ones | ||
} | ||
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#[cfg(test)] | ||
mod tests { | ||
use crate::util::Day; | ||
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use super::Day1; | ||
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const EXAMPLE1: &str = "\ | ||
1abc2\n\ | ||
pqr3stu8vwx\n\ | ||
a1b2c3d4e5f\n\ | ||
treb7uchet"; | ||
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const EXAMPLE2: &str = "\ | ||
two1nine\n\ | ||
eightwothree\n\ | ||
abcone2threexyz\n\ | ||
xtwone3four\n\ | ||
4nineeightseven2\n\ | ||
zoneight234\n\ | ||
7pqrstsixteen"; | ||
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#[test] | ||
fn test_part1() { | ||
assert_eq!(142, Day1::solve(EXAMPLE1).0); | ||
} | ||
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#[test] | ||
fn test_part2() { | ||
assert_eq!(281, Day1::solve(EXAMPLE2).1); | ||
} | ||
} |
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use day1::Day1; | ||
use util::{read_input, Day}; | ||
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mod day1; | ||
mod util; | ||
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fn main() { | ||
let day1 = solve(1); | ||
println!("Day1 = {day1:?}"); | ||
} | ||
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fn solve(day: u8) -> (usize, usize) { | ||
let input = &read_input(day).unwrap(); | ||
match day { | ||
1 => Day1::solve(input), | ||
_ if day > 25 => unreachable!("There are only 25 days!"), | ||
_ => todo!("Not done!"), | ||
} | ||
} |