advent-of-code/src/bin/p01.rs

use std::collections::BTreeSet;
use std::fs;
use std::io::{self, BufRead};

fn main() {
    let filename = "etc/p01.txt";
    let file = fs::File::open(filename).expect("Can't open file");
    let lines = io::BufReader::new(file).lines();

    let mut set = BTreeSet::new();
    let mut cur_cals: u32 = 0;
    for l in lines {
        match l.expect("Can't read line.").parse::<u32>() {
            Ok(cals) => {
                cur_cals += cals;
            }
            _ => {
                set.insert(cur_cals);
                println!(
                    "new cals: {}, max so far: {}",
                    cur_cals,
                    set.last().unwrap()
                );
                cur_cals = 0;
            }
        }
    }

    if cur_cals > 0 {
        set.insert(cur_cals);
    }

    let total: u32 = set.iter().rev().take(3).sum();
    println!("calories of top 3 are: {}", total);
}