pub struct DaryHeapWithMap<N, K, const D: usize = 2>where
    N: Eq + Hash + Clone,
    K: PartialOrd + Clone,{ /* private fields */ }
Expand description

A d-ary heap which implements both PriorityQueue and PriorityQueueDecKey.

See PriorityQueueDecKey for additional functionalities.

DaryHeapWithMap achieves the additional features by making use of a map of nodes to positions on the heap.

Examples

Heap as a PriorityQueue

Usage of d-ary heap as a basic priority queue.

use orx_priority_queue::*;

fn test_priority_queue<P>(mut pq: P)
where
    P: PriorityQueue<usize, f64>
{
    pq.clear();
     
    pq.push(0, 42.0);
    assert_eq!(Some(&(0, 42.0)), pq.peek());

    pq.push(1, 7.0);
    assert_eq!(Some(&(1, 7.0)), pq.peek());

    let popped = pq.pop();
    assert_eq!(Some((1, 7.0)), popped);

    let popped = pq.pop();
    assert_eq!(Some((0, 42.0)), popped);

    assert!(pq.is_empty());
}

// d-ary heap using a hash map to locate existing nodes (although decrease-key is not used here)
test_priority_queue(DaryHeapWithMap::<_, _, 3>::default());
test_priority_queue(DaryHeapWithMap::<_, _, 4>::with_capacity(16));
// using type aliases to simplify signatures
test_priority_queue(BinaryHeapWithMap::default());
test_priority_queue(BinaryHeapWithMap::with_capacity(16));
test_priority_queue(TernaryHeapWithMap::default());
test_priority_queue(TernaryHeapWithMap::with_capacity(16));
test_priority_queue(QuarternaryHeapWithMap::default());
test_priority_queue(QuarternaryHeapWithMap::with_capacity(16));

Heap as a PriorityQueueDecKey

Usage of a d-ary heap as a priority queue with decrease key operation and its variants.

use orx_priority_queue::*;

fn test_priority_queue_deckey<P>(mut pq: P)
where
    P: PriorityQueueDecKey<usize, f64>
{
    pq.clear();
     
    pq.push(0, 42.0);
    assert_eq!(Some(&(0, 42.0)), pq.peek());

    pq.push(1, 17.0);
    assert_eq!(Some(&(1, 17.0)), pq.peek());

    pq.decrease_key(&0, &7.0);
    assert_eq!(Some(&(0, 7.0)), pq.peek());

    let is_key_decreased = pq.try_decrease_key(&1, &20.0);
    assert!(!is_key_decreased);

    let popped = pq.pop();
    assert_eq!(Some((0, 7.0)), popped);

    let popped = pq.pop();
    assert_eq!(Some((1, 17.0)), popped);

    assert!(pq.is_empty());
}
// d-ary heap using a hash map to locate existing nodes
test_priority_queue_deckey(DaryHeapWithMap::<_, _, 3>::default());
test_priority_queue_deckey(DaryHeapWithMap::<_, _, 4>::with_capacity(16));
// using type aliases to simplify signatures
test_priority_queue_deckey(BinaryHeapWithMap::default());
test_priority_queue_deckey(BinaryHeapWithMap::with_capacity(16));
test_priority_queue_deckey(TernaryHeapWithMap::default());
test_priority_queue_deckey(TernaryHeapWithMap::with_capacity(16));
test_priority_queue_deckey(QuarternaryHeapWithMap::default());
test_priority_queue_deckey(QuarternaryHeapWithMap::with_capacity(16));

Implementations§

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impl<N, K, const D: usize> DaryHeapWithMap<N, K, D>where N: Eq + Hash + Clone, K: PartialOrd + Clone,

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pub fn with_capacity(capacity: usize) -> Self

Creates a new d-ary heap with the given initial capacity on the number of nodes to simultaneously exist on the heap.

Trait Implementations§

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impl<N, K, const D: usize> Clone for DaryHeapWithMap<N, K, D>where N: Eq + Hash + Clone + Clone, K: PartialOrd + Clone + Clone,

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fn clone(&self) -> DaryHeapWithMap<N, K, D>

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<N, K, const D: usize> Debug for DaryHeapWithMap<N, K, D>where N: Eq + Hash + Clone + Debug, K: PartialOrd + Clone + Debug,

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<N, K, const D: usize> Default for DaryHeapWithMap<N, K, D>where N: Eq + Hash + Clone, K: PartialOrd + Clone,

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fn default() -> Self

Returns the “default value” for a type. Read more
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impl<N, K, const D: usize> PriorityQueue<N, K> for DaryHeapWithMap<N, K, D>where N: Eq + Hash + Clone, K: PartialOrd + Clone,

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fn len(&self) -> usize

Number of elements in the queue.
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fn as_slice(&self) -> &[(N, K)]

Returns the nodes and keys currently in the queue as a slice; not necessarily sorted.
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fn peek(&self) -> Option<&(N, K)>

Returns, without popping, a reference to the foremost element of the queue; returns None if the queue is empty.
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fn clear(&mut self)

Clears the queue.
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fn pop(&mut self) -> Option<(N, K)>

Removes and returns the (node, key) pair with the lowest key in the queue; returns None if the queue is empty.
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fn pop_node(&mut self) -> Option<N>

Removes and returns the node with the lowest key in the queue; returns None if the queue is empty.
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fn pop_key(&mut self) -> Option<K>

Removes and returns the key of the node with the lowest key in the queue; returns None if the queue is empty.
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fn push(&mut self, node: N, key: K)

Pushes the given (node, key) pair to the queue.
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fn push_then_pop(&mut self, node: N, key: K) -> (N, K)

Performs the push with given (node, key) followed by the pop operation. Read more
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fn is_empty(&self) -> bool

Returns whether he queue is empty or not.
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impl<N, K, const D: usize> PriorityQueueDecKey<N, K> for DaryHeapWithMap<N, K, D>where N: Eq + Hash + Clone, K: PartialOrd + Clone,

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fn contains(&self, node: &N) -> bool

Returns whether the given node is in the queue or not.
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fn key_of(&self, node: &N) -> Option<K>

Returns the key of the given node if it is in the queue; returns None otherwise.
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fn decrease_key(&mut self, node: &N, decreased_key: &K)

Decreases key of the node which is already in the queue to the given decreased_key. This method is commonly use to increase priority of a node; rather than to re-insert it to keep the size of the queue smaller. Read more
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fn update_key(&mut self, node: &N, new_key: &K) -> bool

Updates key of the node which is already in the queue as the given new_key; and returns whether the node’s key is strictly decreased or not. Read more
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fn remove(&mut self, node: &N) -> K

Removes the node from the queue; and returns its current key. Read more
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fn try_decrease_key(&mut self, node: &N, new_key: &K) -> bool

This method: Read more
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fn decrease_key_or_push(&mut self, node: &N, key: &K) -> bool

This method Read more
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fn update_key_or_push(&mut self, node: &N, key: &K) -> bool

This method Read more
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fn try_decrease_key_or_push(&mut self, node: &N, key: &K) -> bool

This method Read more

Auto Trait Implementations§

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impl<N, K, const D: usize> RefUnwindSafe for DaryHeapWithMap<N, K, D>where K: RefUnwindSafe, N: RefUnwindSafe,

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impl<N, K, const D: usize> Send for DaryHeapWithMap<N, K, D>where K: Send, N: Send,

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impl<N, K, const D: usize> Sync for DaryHeapWithMap<N, K, D>where K: Sync, N: Sync,

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impl<N, K, const D: usize> Unpin for DaryHeapWithMap<N, K, D>where K: Unpin, N: Unpin,

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impl<N, K, const D: usize> UnwindSafe for DaryHeapWithMap<N, K, D>where K: UnwindSafe, N: UnwindSafe,

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.