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@MikuroXina
MikuroXina / crc.rs
Created November 6, 2024 20:32
Example implementation of CRC-32 with Rust.
#[derive(Debug, Clone)]
pub struct Crc32 {
table: [u32; 256],
}
impl Crc32 {
pub const SOURCE: u32 = 0xedb8_8320;
pub fn new() -> Self {
let mut table = [0u32; 256];
@MikuroXina
MikuroXina / algo_x.rs
Last active October 11, 2024 10:50
An implementation of Knuth's Algorithm X and Dancing Linked List with Rust.
pub fn algorithm_x(
list: &mut DancingLinkedList,
stack: &mut Vec<usize>,
solutions: &mut Vec<Vec<usize>>,
) {
if list.is_empty() {
solutions.push(stack.clone());
return;
}
@MikuroXina
MikuroXina / lr0.rs
Created June 1, 2024 03:40
The example implementation of full-scratch LR(0) parser.
//! The example implementation of full-scratch LR(0) parser, referenced [Wikipedia](https://en.wikipedia.org/wiki/LR_parser).
//!
//! # Rules
//!
//! There are non-terminal terms: Start, Expr and Bool. And there are terminal
//! terms: 0, 1, +. * and $ (end of input).
//!
//! 1. Introduction: `Start :- Expr $`
//! 2. Expr from multiplication: `Expr :- Expr * Bool`
//! 3. Expr from addition: `Expr :- Expr + Bool`
@MikuroXina
MikuroXina / trie.rs
Created May 17, 2024 15:51
Trie tree implementation with Rust.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct TrieNode<const L: usize> {
children: [Option<Box<TrieNode<L>>>; L],
words: usize,
}
impl<const L: usize> TrieNode<L> {
fn new() -> Self {
TrieNode {
children: std::array::from_fn(|_| None),
@MikuroXina
MikuroXina / counter.rs
Created February 27, 2024 14:15
Items counter with Rust
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Counter<T: Eq + std::hash::Hash> {
counts: std::collections::HashMap<T, usize>,
}
impl<T, Q> std::ops::Index<&Q> for Counter<T>
where
T: Eq + std::hash::Hash + std::borrow::Borrow<Q>,
Q: Eq + std::hash::Hash + ?Sized,
{
@MikuroXina
MikuroXina / discrete_log.rs
Created November 15, 2023 04:58
Pollard's rho algorithm for logarithms in Rust.
/// Finds `x` where `alpha` ** `x` == `beta`.
pub fn discrete_log<const MOD_1: u64, const MOD: u64>(alpha: ModInt<MOD>, beta: ModInt<MOD>) -> Option<u64> {
assert_eq!(MOD_1 + 1, MOD);
fn step<const MOD_1: u64, const MOD: u64>(alpha: ModInt<MOD>, beta: ModInt<MOD>, x: &mut ModInt<MOD>, a: &mut ModInt<MOD_1>, b: &mut ModInt<MOD_1>) {
match x.as_u64() % 3 {
0 => {
*x = *x * *x;
*a = *a * 2.into();
*b = *b * 2.into();
}
@MikuroXina
MikuroXina / range_q.rs
Last active November 15, 2023 23:37
Querying group sum of range by event sourcing method with Rust.
/// Group must satisfy:
/// ```rs
/// fn test<G: Group>(m: G, n: G, l: G) {
/// assert_eq!(m.op(&G::id()), m);
/// assert_eq!(G::id().op(&m), m);
/// assert_eq!(m.op(&n.op(&l)), m.op(&n).op(&l));
/// assert_eq!(m.op(&m.inv()), G::id());
/// assert_eq!(m.inv().op(&m), G::id());
/// }
/// ```
@MikuroXina
MikuroXina / cum.rs
Last active November 16, 2023 00:13
Find cumulative sum of numbers with Rust.
pub fn cum<T: Default + std::ops::AddAssign + Copy>(
nums: impl IntoIterator<Item = T>,
) -> impl Iterator<Item = T> {
nums.into_iter().scan(T::default(), |state, item| {
*state += item;
Some(*state)
})
}
pub fn cum2<T: Default + std::ops::AddAssign + Copy, NNS, NS>(nums: NNS) -> Vec<Vec<T>>
@MikuroXina
MikuroXina / alt_sum.rs
Created November 5, 2023 23:37
Monoid implementation of alternating sum with Rust.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct AltSum {
sum: i64,
len: usize,
}
impl AltSum {
pub fn empty() -> Self {
Self { sum: 0, len: 0 }
}
@MikuroXina
MikuroXina / y.ts
Created October 29, 2023 09:08
Y fixed combinator with TypeScript.
export type Paradoxical<A, R> = (f: Paradoxical<A, R>) => (a: A) => R;
export const Y = <A, R>(f: (g: (a: A) => R) => (a: A) => R): ((a: A) => R) =>
((x: Paradoxical<A, R>) => f((lazy) => x(x)(lazy)))(
(x: Paradoxical<A, R>) => f((lazy) => x(x)(lazy)),
);