I keep getting ParseIntError { kind: InvalidDigit } in my Rust program and I have no idea why

Question

I am writing a paper about how python and Rust differ when used on coding challenges. I have to preface this with the fact that this is my first Rust program ever. So sorry if I'm doing some weird stuff. However, when I am looping through some input in Rust, I get this error:

2
4
1
2
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ParseIntError { kind: InvalidDigit }', src\main.rs:24:14

Here is my code:

use std::fs::File;
use std::io::{Read};
use std::cmp;

fn main() {
    let mut file = File::open("C:\\Users\\isaak\\OneDrive\\skewl\\Fall 2019\\Operating Systems\\rustyboi\\src\\bus.txt").expect("Can't Open File");
    let mut contents = String::new();
    file.read_to_string(&mut contents).expect("Can't Read File");

    let tokens:Vec<&str> = contents.split("\n").collect();

    let l1:Vec<&str> = tokens[0].split(" ").collect();
    let _n = l1[0];
    let w = l1[1];
    //println!("{}", w);

    let l2 = tokens[1].split(" ");

    let mut k = 0;
    let mut maxed = 0;
    let mut mined = 0;
    for item in l2 { // in range n
        println!("{}", item);
        k += item.parse::<i32>().unwrap();
        maxed = cmp::max(k, maxed);
        mined = cmp::min(k, mined);
    }
    println!("{}", cmp::max(w.parse::<i32>().unwrap() - maxed + mined.abs() + 1, 0));
}

The file that it is looking at only contains this:

4 10
2 4 1 2

I am not sure how I could be getting that error on the k+= part in the for loop when the printed value is definitely a number. Anyway, here is a link to the coding challenge in case you are curious: https://codeforces.com/contest/978/problem/E

Answer 1

The working solution in Rust Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=ed17ea24cfcf4b45549846a5c9f1edfd

Your file contains \r\n ends of line ("4 10\r\n2 4 1 2\r\n"), and after splitting by only \n there is \r at the end of each line, therefore parsing fails (\r cannot be parsed into integer).

1. Use lines() instead of split("\n") as a cross-platform solution.
2. You may use split_whitespace() instead of split(" ").