Advent Of Code 2022 (Day 1) in Rust

day1.rs

use std::fs;

fn sort_desc<T: Ord>(v: &mut Vec<T>) {
    v.sort_by(|a, b| b.cmp(a));
}

/// # Advent Of Code 2022 (Day 1).
///
/// Challenge is you an input which displays "calories of elves" ([link](https://adventofcode.com/2022/day/1)):
///
/// `
/// 4525 \
/// 4368 /  elf 1
///
/// 17242 > elf 2
///
/// 10920 \
/// 14072 / elf 3
/// `
///
/// ## Part 1
/// Find the elf with the most total calories.
///
/// ## Part 2
/// Compute the total of the calories of the top 3 elves.
///
fn main() {
    let input = fs::read_to_string("./src/input.txt").unwrap();

    let groups = input
        .split("\n\n")
        .map(|group| group.lines().map(|l| l.parse::<u64>().unwrap()));

    let mut cals: Vec<u64> = groups.map(|group| group.sum()).collect();
    sort_desc(&mut cals);

    let most_cals = cals[0];
    println!("Most Calories: {most_cals:?}");

    let top_total = cals.iter().take(3).sum::<u64>();
    println!("Total Calories (Top 3): {top_total:?}");
}