Converts the store s into a heap. If initialSize is specified, only the first initialSize elements in s are transformed into a heap, after which the heap can grow up to r.length (if Store is a range) or indefinitely (if Store is a container with insertBack). Performs O(min(r.length, initialSize)) evaluations of less.
A postblit is present on this object, but not explicitly documented in the source.
Removes the largest element from the heap.
Takes ownership of a store. After this, manipulating s may make the heap work incorrectly.
Takes ownership of a store assuming it already was organized as a heap.
If the heap has room to grow, inserts value into the store and returns true. Otherwise, if less(value, front), calls replaceFront(value) and returns again true. Otherwise, leaves the heap unaffected and returns false. This method is useful in scenarios where the smallest k elements of a set of candidates must be collected.
Swapping is allowed if the heap is full. If less(value, front), the method exchanges store.front and value and returns true. Otherwise, it leaves the heap unaffected and returns false.
Inserts value into the store. If the underlying store is a range and length == capacity, throws an AssertException.
Removes the largest element from the heap and returns it. The element still resides in the heap's store. For performance reasons you may want to use removeFront with heaps of objects that are expensive to copy.
Removes the largest element from the heap.
Replaces the largest element in the store with value.
Returns the capacity of the heap, which is the length of the underlying store (if the store is a range) or the capacity of the underlying store (if the store is a container).
Returns true if the heap is empty, false otherwise.
Returns a front of the heap, which is the largest element according to less.
Returns the length of the heap.
The payload includes the support store and the effective length
Example from "Introduction to Algorithms" Cormen et al, p 146
import mir.algorithm.iteration : equal; int[] a = [ 4, 1, 3, 2, 16, 9, 10, 14, 8, 7 ]; auto h = heapify(a); // largest element assert(h.front == 16); // a has the heap property assert(equal(a, [ 16, 14, 10, 8, 7, 9, 3, 2, 4, 1 ]));
BinaryHeap implements the standard input range interface, allowing lazy iteration of the underlying range in descending order.
import mir.algorithm.iteration : equal; import std.range : takeExactly; int[] a = [4, 1, 3, 2, 16, 9, 10, 14, 8, 7]; auto heap = heapify(a); auto top5 = (&heap).takeExactly(5); assert(top5.equal([16, 14, 10, 9, 8]));
Implements a binary heap container on top of a given random-access range type (usually T[]) or a random-access container type (usually Array!T). The documentation of BinaryHeap will refer to the underlying range or container as the store of the heap.
The binary heap induces structure over the underlying store such that accessing the largest element (by using the front property) is a O(1) operation and extracting it (by using the removeFront() method) is done fast in O(log n) time.
If less is the less-than operator, which is the default option, then BinaryHeap defines a so-called max-heap that optimizes extraction of the largest elements. To define a min-heap, instantiate BinaryHeap with "a > b" as its predicate.
Simply extracting elements from a BinaryHeap container is tantamount to lazily fetching elements of Store in descending order. Extracting elements from the BinaryHeap to completion leaves the underlying store sorted in ascending order but, again, yields elements in descending order.
If Store is not a container, the BinaryHeap cannot grow beyond the size of that range. If Store is a container that supports insertBack, the BinaryHeap may grow by adding elements to the container.