dec1 part 2

main.rs

use std::io;

fn main() {

  let mut captcha = String::new();
  io::stdin().read_line(&mut captcha)
    .expect("Failed to read line");
  let captcha = captcha.trim();

  let mut chars = captcha.chars().cycle();
  let mut total: u32 = 0;
  for _ in 0..captcha.len() {
    let c = chars.next();
    match chars.nth(captcha.len() / 2 - 1) {
      Some(d) if Some(d) == c   => {
        total += d.to_string().parse()
          .expect("Failed to parse digit");
      },  
      _                         => (), 
    }   
  }
  println!("Total: {}", total);
}