day-6.rs

use std::fs;
use std::collections::HashSet;
use std::collections::VecDeque;

fn main() {

    for marker_length in vec![4, 14] {
        let file_str = fs::read_to_string("day-6.input").expect("Failed to read file");

        let mut marker : VecDeque<char> = VecDeque::new();
        let mut index : usize = 0;

        for (i, ch) in file_str.trim().chars().enumerate() {
            marker.push_front(ch);
            if marker.len() > marker_length {
                marker.pop_back();
            }

            let marker_uniq : HashSet<char> = marker.iter().map(|&x| x).collect();
            if marker_uniq.len() == marker_length {
                index = i + 1;
                break;
            }
        }

        println!("{:?}", index);
    }
}