package core_kernel
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sha256=34a0288f16027c6b90e4ad16cb5cc677d7063d310faf918748ce70f1745116c0
doc/core_kernel.pairing_heap/Pairing_heap/index.html
Module Pairing_heap
Source
Heap implementation based on a pairing-heap.
This heap implementations supports an arbitrary element type via a comparison function.
of_sexp and bin_io functions aren't supplied for heaps due to the difficulties in reconstructing the correct comparison function when de-serializing.
Mutation of the heap during iteration is not supported, but there is no check to prevent it. The behavior of a heap that is mutated during iteration is undefined.
Even though these two functions min_elt
and max_elt
are part of Container.S1, they are documented separately to make sure there is no confusion. They are independent of the comparison function used to order the heap. Instead, a traversal of the entire structure is done using the provided compare
function to find a min or max.
If you want to access the smallest element of the heap according to the heap's comparison function in constant time, you should use top
.
create ?min_size ~cmp
returns a new min-heap that can store min_size
elements without reallocations, using ordering function cmp
.
The top of the heap is the smallest element as determined by the provided comparison function. In particular, if cmp x y < 0
then x
will be "on top of" y
in the heap.
Memory use can be surprising in that the underlying pool never shrinks, so current memory use will at least be proportional to the largest number of elements that the heap has ever held.
min_size
(see create
) will be set to the size of the input array or list.
Removes all elements, leaving an empty heap. This operation is O(n) where n is the size of the heap.
pop_if t cond
returns Some top_element
of t
if it satisfies condition cond
, removing it, or None
in any other case.
add_removable t v
adds v
to t
, returning a token that can be used to delete v
from t
in lg(n) amortized time.
Note that while add
doesn't allocate unless the underlying pool needs to be resized, add_removable
always allocates. The Unsafe
module has a non-allocating alternative.
If t
and token
are mismatched then behavior is undefined. Trying to remove
an already removed token (by an earlier call to remove
or pop
for instance) is a no-op, but keeping token
around after it has been removed may lead to memory leaks since it has a reference to the heap.
update t token v
is shorthand for remove t token; add_removable t v
.
find_elt t ~f
. If f
is true for some element in t
, return an Elt.t
for that element. This operation is O(n).