itertools/
extrema_set.rs

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

itertools/
extrema_set.rs
