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extrema_set.rs
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/
extrema_set.rs
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/// Implementation guts for `min_set`, `min_set_by`, and `min_set_by_key`.
pub fn min_set_impl<I, K, F, L>(mut it: I,
mut key_for: F,
mut lt: L) -> Option<Vec<I::Item>>
where I: Iterator,
F: FnMut(&I::Item) -> K,
L: FnMut(&I::Item, &I::Item, &K, &K) -> bool,
{
let (mut result, mut current_key) = match it.next() {
None => return None,
Some(element) => {
let key = key_for(&element);
(vec![element], key)
}
};
for element in it {
let key = key_for(&element);
if lt(&element, &result[0], &key, ¤t_key) {
result.clear();
result.push(element);
current_key = key;
} else if !lt(&result[0], &element, ¤t_key, &key) {
result.push(element);
}
}
Some(result)
}
/// Implementation guts for `ax_set`, `max_set_by`, and `max_set_by_key`.
pub fn max_set_impl<I, K, F, L>(it: I,
key_for: F,
mut lt: L) -> Option<Vec<I::Item>>
where I: Iterator,
F: FnMut(&I::Item) -> K,
L: FnMut(&I::Item, &I::Item, &K, &K) -> bool,
{
min_set_impl(it, key_for, |it1, it2, key1, key2| lt(it2, it1, key2, key1))
}