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/// --- Part Two ---
///
/// As you finish identifying the misplaced items, the Elves come to you with another issue.
///
/// For safety, the Elves are divided into groups of three. Every Elf carries a badge that
/// identifies their group. For efficiency, within each group of three Elves, the badge is the
/// only item type carried by all three Elves. That is, if a group's badge is item type B, then
/// all three Elves will have item type B somewhere in their rucksack, and at most two of the Elves
/// will be carrying any other item type.
///
/// The problem is that someone forgot to put this year's updated authenticity sticker on the
/// badges. All of the badges need to be pulled out of the rucksacks so the new authenticity
/// stickers can be attached.
///
/// Additionally, nobody wrote down which item type corresponds to each group's badges. The only
/// way to tell which item type is the right one is by finding the one item type that is common
/// between all three Elves in each group.
///
/// Every set of three lines in your list corresponds to a single group, but each group can have a
/// different badge item type. So, in the above example, the first group's rucksacks are the first
/// three lines:
///
/// ```
/// vJrwpWtwJgWrhcsFMMfFFhFp
/// jqHRNqRjqzjGDLGLrsFMfFZSrLrFZsSL
/// PmmdzqPrVvPwwTWBwg
/// ```
///
/// And the second group's rucksacks are the next three lines:
///
/// ```
/// wMqvLMZHhHMvwLHjbvcjnnSBnvTQFn
/// ttgJtRGJQctTZtZT
/// CrZsJsPPZsGzwwsLwLmpwMDw
/// ```
///
/// In the first group, the only item type that appears in all three rucksacks is lowercase r; this
/// must be their badges. In the second group, their badge item type must be Z.
///
/// Priorities for these items must still be found to organize the sticker attachment efforts:
/// here, they are 18 (r) for the first group and 52 (Z) for the second group. The sum of these is
/// 70.
///
/// Find the item type that corresponds to the badges of each three-Elf group. What is the sum of
/// the priorities of those item types?
use clap::Parser;
use itertools::Itertools;
use std::fs::File;
use std::io::prelude::*;
use std::io::BufReader;
use std::path::PathBuf;
const FILEPATH: &'static str = "examples/input.txt";
#[derive(Parser, Debug)]
#[clap(author, version, about, long_about = None)]
struct Cli {
#[clap(short, long, default_value = FILEPATH)]
file: PathBuf,
}
fn main() {
let args = Cli::parse();
let file = File::open(&args.file).unwrap();
let reader = BufReader::new(file);
let res = reader
.lines()
.map(|l| l.unwrap())
.chunks(3)
.into_iter()
.map(|iter| {
let (top, middle, bottom) = iter.collect_tuple::<(String, String, String)>().unwrap();
top.chars()
.filter(|t| middle.contains(*t) && bottom.contains(*t))
.map(|l| {
let b = l as u8;
if b > b'a' {
(b - b'a') as u16 + 1
} else {
(b - b'A') as u16 + 27
}
})
.next()
.unwrap()
})
.sum::<u16>();
println!(
"The sum of the priorities of the item that appear in both compartments of each rucksack is {}",
res
);
}
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