itertools/
extrema_set.rs

1#![cfg(feature = "use_alloc")]
2use alloc::{vec, vec::Vec};
3use std::cmp::Ordering;
4
5/// Implementation guts for `min_set`, `min_set_by`, and `min_set_by_key`.
6pub fn min_set_impl<I, K, F, Compare>(
7    mut it: I,
8    mut key_for: F,
9    mut compare: Compare,
10) -> Vec<I::Item>
11where
12    I: Iterator,
13    F: FnMut(&I::Item) -> K,
14    Compare: FnMut(&I::Item, &I::Item, &K, &K) -> Ordering,
15{
16    match it.next() {
17        None => Vec::new(),
18        Some(element) => {
19            let mut current_key = key_for(&element);
20            let mut result = vec![element];
21            it.for_each(|element| {
22                let key = key_for(&element);
23                match compare(&element, &result[0], &key, &current_key) {
24                    Ordering::Less => {
25                        result.clear();
26                        result.push(element);
27                        current_key = key;
28                    }
29                    Ordering::Equal => {
30                        result.push(element);
31                    }
32                    Ordering::Greater => {}
33                }
34            });
35            result
36        }
37    }
38}
39
40/// Implementation guts for `ax_set`, `max_set_by`, and `max_set_by_key`.
41pub fn max_set_impl<I, K, F, Compare>(it: I, key_for: F, mut compare: Compare) -> Vec<I::Item>
42where
43    I: Iterator,
44    F: FnMut(&I::Item) -> K,
45    Compare: FnMut(&I::Item, &I::Item, &K, &K) -> Ordering,
46{
47    min_set_impl(it, key_for, |it1, it2, key1, key2| {
48        compare(it2, it1, key2, key1)
49    })
50}
itertools/extrema_set.rs

itertools/
extrema_set.rs
