Crate priority_queue[][src]

This crate provide a priority queue backed by an hashmap with some efficient methods to change the priority of an element in O(log(N)) time (worst case).

The elements (called Items, of type I) must implement Hash and Eq traits.

This can frequently be achieved by using #[derive(PartialEq, Eq, Hash)]. If you implement these yourself, it is important that the following property holds:

k1 == k2 -> hash(k1) == hash(k2)

In other words, if two keys are equal, their hashes must be equal.

The priority P may be any type that implements Ord. For reverse order remember the standard wrapper Reverse<T>


use priority_queue::PriorityQueue;

fn main() {
    let mut pq = PriorityQueue::new();

    pq.push("Apples", 5);
    pq.push("Bananas", 8);
    pq.push("Strawberries", 23);

    assert_eq!(pq.peek(), Some((&"Strawberries", &23)));

    pq.change_priority("Bananas", 25);
    assert_eq!(pq.peek(), Some((&"Bananas", &25)));

    for (item, _) in pq.into_sorted_iter() {
        println!("{}", item);



A priority queue with efficient change function to change the priority of an element.