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use std::cmp::Ordering;
/// Implementation guts for `min_set`, `min_set_by`, and `min_set_by_key`.
pub fn min_set_impl<I, K, F, Compare>(
mut it: I,
mut key_for: F,
mut compare: Compare,
) -> Vec<I::Item>
where
I: Iterator,
F: FnMut(&I::Item) -> K,
Compare: FnMut(&I::Item, &I::Item, &K, &K) -> Ordering,
{
match it.next() {
None => Vec::new(),
Some(element) => {
let mut current_key = key_for(&element);
let mut result = vec![element];
it.for_each(|element| {
let key = key_for(&element);
match compare(&element, &result[0], &key, ¤t_key) {
Ordering::Less => {
result.clear();
result.push(element);
current_key = key;
}
Ordering::Equal => {
result.push(element);
}
Ordering::Greater => {}
}
});
result
}
}
}
/// Implementation guts for `ax_set`, `max_set_by`, and `max_set_by_key`.
pub fn max_set_impl<I, K, F, Compare>(it: I, key_for: F, mut compare: Compare) -> Vec<I::Item>
where
I: Iterator,
F: FnMut(&I::Item) -> K,
Compare: FnMut(&I::Item, &I::Item, &K, &K) -> Ordering,
{
min_set_impl(it, key_for, |it1, it2, key1, key2| {
compare(it2, it1, key2, key1)
})
}