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aoc23_day1_1.rs
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aoc23_day1_1.rs
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use std::collections::VecDeque;
use std::io;
fn main() -> io::Result<()> {
let mut scan = Scan::new();
let mut res = 0u32;
while let Ok(line) = scan.next_line() {
let digits: Vec<u32> = line.chars().filter_map(|c| c.to_digit(10)).collect();
res += digits[0] * 10 + digits.last().unwrap();
}
println!("{}", res);
Ok(())
}
struct Scan {
buffer: VecDeque<String>,
}
impl Scan {
fn new() -> Scan {
Scan {
buffer: VecDeque::new(),
}
}
fn next_line(&self) -> io::Result<String> {
let mut line = String::new();
match io::stdin().read_line(&mut line)? {
0 => Err(io::Error::new(io::ErrorKind::Other, "EOF")),
_ => Ok(line),
}
}
fn next<T: std::str::FromStr>(&mut self) -> T {
loop {
if let Some(token) = self.buffer.pop_front() {
match token.parse() {
Ok(x) => {
return x;
}
_ => {
panic!("parse");
}
}
}
let line = self.next_line().unwrap();
self.buffer = line.split_whitespace().map(String::from).collect();
}
}
}