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static DAY: u8 = 1;
fn main() {
let input = advent::read_lines(DAY);
println!("{DAY}a: {}", list_distance(&input));
println!("{DAY}b: {}", similarity(&input));
}
fn parse_numbers(numbers: &[String]) -> (Vec::<usize>, Vec::<usize>) {
let mut list1 = Vec::new();
let mut list2 = Vec::new();
for pair in numbers {
let (number1, number2) = pair.split_once(" ").unwrap();
list1.push(number1.parse::<usize>().unwrap());
list2.push(number2.parse::<usize>().unwrap());
}
(list1, list2)
}
fn list_distance(numbers: &[String]) -> usize {
let (mut list1, mut list2) = parse_numbers(numbers);
list1.sort();
list2.sort();
list1.iter()
.enumerate()
.map(|(i, number1)| number1.abs_diff(list2[i]))
.sum()
}
fn similarity(numbers: &[String]) -> usize {
let (list1, list2) = parse_numbers(numbers);
list1.iter()
.map(|x| x * list2.iter().filter(|&y| x == y).count())
.sum()
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test() {
let input = [
"3 4",
"4 3",
"2 5",
"1 3",
"3 9",
"3 3",
].iter().map(|&x| String::from(x)).collect::<Vec<_>>();
assert_eq!(list_distance(&input), 11);
assert_eq!(similarity(&input), 31);
}
}
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