Remove the parentheses

parentheses.rs

use std::collections::LinkedList;
use std::iter::FromIterator;

fn remove_parentheses(s: &str) -> String {
    let w: LinkedList<char> = s.chars().collect();
    let mut skip_count = 0;
    String::from_iter(w.into_iter().filter_map(|l| {
        if l == '(' { skip_count += 1 }
        let r = if skip_count != 0 { 
            None 
        } else {
            Some(l)
        };
        if l == ')' { skip_count -= 1 }
        r
    }).collect::<Vec<char>>())
}