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Group Iterator definitions

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asonix 2024-05-26 13:41:26 -05:00
parent b9feba74a4
commit 81c183dbcc
1 changed files with 49 additions and 50 deletions
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99
src/lib.rs
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@ -32,32 +32,6 @@ pub struct ChoosePermute<'a, T, const SIZE: usize> {
permute: Option<Permute<T, SIZE>>,
}
impl<'a, T: Clone, const SIZE: usize> Iterator for ChoosePermute<'a, T, SIZE> {
type Item = [T; SIZE];
fn next(&mut self) -> Option<Self::Item> {
loop {
if let Some(permute) = self.permute.as_mut() {
if let Some(item) = permute.next() {
return Some(item);
}
self.permute.take();
}
let chosen = self.choose.next()?;
self.permute = Some(permute(chosen));
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let size = self.choose.size_hint().0 * factorial(SIZE);
(size, Some(size))
}
}
pub struct Choose<'a, T, const SIZE: usize> {
source: &'a [T],
count: [usize; SIZE],
@ -102,30 +76,6 @@ impl<'a, T: Clone, const SIZE: usize> Choose<'a, T, SIZE> {
})
}
}
impl<'a, T: Clone, const SIZE: usize> Iterator for Choose<'a, T, SIZE> {
type Item = [T; SIZE];
fn next(&mut self) -> Option<Self::Item> {
if self.closed {
None
} else {
self.increment();
Some(self.choose())
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let numerator = factorial(self.source.len());
let denominator = factorial(SIZE) * factorial(self.source.len() - SIZE);
let size = numerator / denominator;
(size, Some(size))
}
}
impl<T: Clone, const SIZE: usize> Permute<T, SIZE> {
fn increment(&mut self) {
let mut any_updated = false;
@ -164,6 +114,55 @@ fn factorial(num: usize) -> usize {
(1..=num).fold(1, |acc, item| acc * item)
}
impl<'a, T: Clone, const SIZE: usize> Iterator for ChoosePermute<'a, T, SIZE> {
type Item = [T; SIZE];
fn next(&mut self) -> Option<Self::Item> {
loop {
if let Some(permute) = self.permute.as_mut() {
if let Some(item) = permute.next() {
return Some(item);
}
self.permute.take();
}
let chosen = self.choose.next()?;
self.permute = Some(permute(chosen));
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let size = self.choose.size_hint().0 * factorial(SIZE);
(size, Some(size))
}
}
impl<'a, T: Clone, const SIZE: usize> Iterator for Choose<'a, T, SIZE> {
type Item = [T; SIZE];
fn next(&mut self) -> Option<Self::Item> {
if self.closed {
None
} else {
self.increment();
Some(self.choose())
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let numerator = factorial(self.source.len());
let denominator = factorial(SIZE) * factorial(self.source.len() - SIZE);
let size = numerator / denominator;
(size, Some(size))
}
}
impl<T: Clone, const SIZE: usize> Iterator for Permute<T, SIZE> {
type Item = [T; SIZE];