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#![allow(unused)]
mod macros;
use std::str::{self};
use std::io::{stdin, stdout, BufRead, BufWriter, Write};
pub struct Scanner<R> {
reader: R,
buffer: Vec<String>,
}
impl<R: BufRead> Scanner<R> {
pub fn new(reader: R) -> Self {
Self {
reader,
buffer: vec![],
}
}
pub fn next<T: str::FromStr>(&mut self) -> T {
loop {
if let Some(token) = self.buffer.pop() {
return token.parse().ok().expect("Failed to parse");
}
let mut input = String::new();
self.reader.read_line(&mut input).expect("Failed to read");
self.buffer = input.split_whitespace().rev().map(String::from).collect();
}
}
}
pub struct UnsafeScanner<R> {
reader: R,
buf_str: Vec<u8>,
buf_iter: str::SplitAsciiWhitespace<'static>,
}
impl<R: BufRead> UnsafeScanner<R> {
pub fn new(reader: R) -> Self {
Self {
reader,
buf_str: vec![],
buf_iter: "".split_ascii_whitespace(),
}
}
pub fn token<T: str::FromStr>(&mut self) -> T {
loop {
if let Some(token) = self.buf_iter.next() {
return token.parse().ok().expect("Failed parse");
}
self.buf_str.clear();
self.reader
.read_until(b'\n', &mut self.buf_str)
.expect("Failed read");
self.buf_iter = unsafe {
let slice = str::from_utf8_unchecked(&self.buf_str);
std::mem::transmute(slice.split_ascii_whitespace())
}
}
}
}
pub fn rand_c(){}
pub fn hashmap(){}
pub fn copy_splice(){}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_new_scanner() {
let input: &[u8] = b"50 30";
let mut scan = Scanner::new(input);
let mut out = vec![];
let x = scan.next::<i32>();
let y = scan.next::<i32>();
writeln!(out, "{} - {} = {}", x, y, x - y).ok();
assert_eq!(out, b"50 - 30 = 20\n")
}
#[test]
fn test_unsafe_scanner() {
let input: &[u8] = b"50 30";
let mut scan = UnsafeScanner::new(input);
let mut out = vec![];
let x = scan.token::<i32>();
let y = scan.token::<i32>();
writeln!(out, "{} - {} = {}", x, y, x - y).ok();
assert_eq!(out, b"50 - 30 = 20\n");
}
}