use std::error::Error;
use std::fs;
use std::collections::HashMap;
use std::str;


pub fn both(filename: &str) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(filename)?;

    let mut answers: HashMap<u8, bool> = HashMap::new();
    let mut sum = 0;
    for line in contents.lines() {
        if line.trim() == "" {
            sum += answers.len();
            answers = HashMap::new();
            continue
        }

        for byte in line.as_bytes() {
            answers.insert(*byte, true);
        }
    }
    sum += answers.len();
    println!("sum of group unique questions with yes: {}", sum);
    answers = HashMap::new();

    let mut first = true;
    sum = 0;
    for line in contents.lines() {
        if line.trim() == "" {
            sum += answers.len();
            answers = HashMap::new();
            first = true;
            continue
        }
        if first {
            for byte in line.as_bytes() {
                answers.insert(*byte, true);
            }
            first = false;
        } else {
            answers.retain(|k, _| line.as_bytes().contains(k));
        }
    }
    sum += answers.len();
    println!("sum of group questions with all yes: {}", sum);

    Ok(())
}