// Copyright 2022 Christian Ulrich
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
// usage: ./part1 < input

pub mod common;

use common::Token;

fn main() -> Result<(), &'static str> {
    let mut packets = Vec::new();
    for pair in common::packet_pairs() {
        let (left, right) = pair?;
        packets.push(left);
        packets.push(right);
    }
    let divider1 = Token::from_str("[[2]]")?;
    let divider2 = Token::from_str("[[6]]")?;
    packets.push(divider1.clone());
    packets.push(divider2.clone());
    packets.sort();
    let divider1_pos = packets.iter().position(|p| p == &divider1).unwrap() + 1;
    let divider2_pos = packets.iter().position(|p| p == &divider2).unwrap() + 1;
    println!("{}", divider1_pos * divider2_pos);
    Ok(())
}