#input #stdin #competetive #kattis #fast-input


Fast and easy input from standard in, made for competetive programming

7 releases

0.1.6 Mar 26, 2021
0.1.5 Dec 19, 2020
0.1.4 Nov 1, 2020
0.1.2 Oct 31, 2020

#73 in Parser tooling

46 downloads per month

MIT license

266 lines


FastInput - Read input, fast!

FastInput is aimed to simplify reading of known input from stdin, mainly in a competetive programming environment. The crate exposes the FastInput struct which contains methods for reading and parsing line-based input. FastInput does no validation of the input and uses unsafe operations and buffering to achieve great performance.


The following example creates a new FastInput and reads some input:

use fast_input::{FastInput, Str};

let input = FastInput::new();
let first_line = input.next_line();

// Type arguments can often be omitted as rust is awesome,
// specified here for clarity.
let (a, b): (u32, u32) = input.next_tuple();

println!("First line was: {}, a + b = {}", first_line, a + b);

// Read a line of integers and collect into a `Vec`
let numbers: Vec<u32> = input.next_as_iter().collect();

// `FastInput` contains methods to read up to quintuples
let (a, b, c, d, e) = input.next_quintuple();
let sum: i32 = 0i32 + a + b + c + d + e;

// The `Str` type can be used to mix string slices with parsed data
let (name, age) = input.next_tuple::<Str, u8>();
// `Str` can be dereferenced into its contained string slice
let name: &str = *name;

// Read all remaining lines and print them
for line in input.lines() {
    println!("{}", line);

No runtime deps