use itertools::Itertools;
use std::error::Error;
use std::fs::File;
use std::io::{self, BufRead};
use std::vec::Vec;

fn main() -> Result<(), Box<dyn Error>> {
    let file = File::open("inputs/day1.txt")?;
    let lines = io::BufReader::new(file).lines();

    let numbers: Vec<u32> = lines.map(|l| l.unwrap().parse().unwrap()).collect();

    let count = 3;

    for combo in numbers.iter().combinations(count) {
        if combo.iter().fold(0u32, |acc, x| acc + **x) == 2020 {
            println!(
                "Combo: {:?} == {}",
                combo,
                combo.iter().fold(1u32, |acc, x| acc * **x)
            );
            break;
        }
    }

    Ok(())
}