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|
use nom::{
character::complete::{line_ending, u32 as nom_u32},
combinator::map,
multi::separated_list1,
sequence::pair,
IResult,
};
use std::fs;
fn main() -> Result<(), Box<dyn std::error::Error>> {
let input = fs::read_to_string("inputs/day_1.txt")?;
let elves = Elves::parser(&input).unwrap().1;
dbg!(elves.max_calories_sum(1));
dbg!(elves.max_calories_sum(3));
Ok(())
}
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
struct Elves {
elves: Vec<Elf>,
}
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
struct Elf {
calories: Vec<u32>,
}
impl Elves {
fn parser(input: &str) -> IResult<&str, Elves> {
map(
separated_list1(pair(line_ending, line_ending), Elf::parser),
Elves::new,
)(input)
}
fn new(mut elves: Vec<Elf>) -> Elves {
elves.sort_unstable_by_key(|elf| elf.total_calories());
Elves { elves }
}
fn max_calories_sum(&self, count: usize) -> u32 {
self.elves
.iter()
.rev()
.take(count)
.map(|elf| elf.total_calories())
.sum()
}
}
impl Elf {
fn parser(input: &str) -> IResult<&str, Elf> {
map(separated_list1(line_ending, nom_u32), |calories| Elf {
calories,
})(input)
}
fn total_calories(&self) -> u32 {
self.calories.iter().sum()
}
}
|
