#![feature(iter_array_chunks)]

use std::{
    collections::{hash_map::RandomState, HashSet},
    fs::File,
    io::{BufRead, BufReader},
    iter::FromIterator,
};

fn main() -> () {
    let input = File::open("input.txt").unwrap();
    let buf = BufReader::new(input);

    let score: u32 = buf.lines().array_chunks::<3>().map(|lines| {
        let intersection = lines.iter().map(|line| {
            HashSet::<_, RandomState>::from_iter(line.as_ref().unwrap().chars())
        }).reduce(|acc, set| acc.intersection(&set).cloned().collect()).unwrap();
        assert!(intersection.len() == 1);
        intersection.into_iter().map(|char| {
            let score: u32 = match char {
                'A'..='Z' => char as u32 - 'A' as u32 + 27,
                'a'..='z' => char as u32 - 'a' as u32 + 1,
                _ => panic!("nigger, that's invalid")
            };
            score
        }).sum::<u32>()
    }).sum();
    println!("{:?}", score);
}