package heap

Import Path
	container/heap (on and

Dependency Relation
	imports one package, and imported by 2 packages

Involved Source Files Package heap provides heap operations for any type that implements heap.Interface. A heap is a tree with the property that each node is the minimum-valued node in its subtree. The minimum element in the tree is the root, at index 0. A heap is a common way to implement a priority queue. To build a priority queue, implement the Heap interface with the (negative) priority as the ordering for the Less method, so Push adds items while Pop removes the highest-priority item from the queue. The Examples include such an implementation; the file example_pq_test.go has the complete source.
Package-Level Type Names (only one)
/* sort by: | */
The Interface type describes the requirements for a type using the routines in this package. Any type that implements it may be used as a min-heap with the following invariants (established after Init has been called or if the data is empty or sorted): !h.Less(j, i) for 0 <= i < h.Len() and 2*i+1 <= j <= 2*i+2 and j < h.Len() Note that Push and Pop in this interface are for package heap's implementation to call. To add and remove things from the heap, use heap.Push and heap.Pop. Len is the number of elements in the collection. Less reports whether the element with index i must sort before the element with index j. If both Less(i, j) and Less(j, i) are false, then the elements at index i and j are considered equal. Sort may place equal elements in any order in the final result, while Stable preserves the original input order of equal elements. Less must describe a transitive ordering: - if both Less(i, j) and Less(j, k) are true, then Less(i, k) must be true as well. - if both Less(i, j) and Less(j, k) are false, then Less(i, k) must be false as well. Note that floating-point comparison (the < operator on float32 or float64 values) is not a transitive ordering when not-a-number (NaN) values are involved. See Float64Slice.Less for a correct implementation for floating-point values. // remove and return element Len() - 1. // add x as element Len() Swap swaps the elements with indexes i and j. T : sort.Interface func Fix(h Interface, i int) func Init(h Interface) func Pop(h Interface) interface{} func Push(h Interface, x interface{}) func Remove(h Interface, i int) interface{}
Package-Level Functions (total 5)
Fix re-establishes the heap ordering after the element at index i has changed its value. Changing the value of the element at index i and then calling Fix is equivalent to, but less expensive than, calling Remove(h, i) followed by a Push of the new value. The complexity is O(log n) where n = h.Len().
Init establishes the heap invariants required by the other routines in this package. Init is idempotent with respect to the heap invariants and may be called whenever the heap invariants may have been invalidated. The complexity is O(n) where n = h.Len().
Pop removes and returns the minimum element (according to Less) from the heap. The complexity is O(log n) where n = h.Len(). Pop is equivalent to Remove(h, 0).
Push pushes the element x onto the heap. The complexity is O(log n) where n = h.Len().
Remove removes and returns the element at index i from the heap. The complexity is O(log n) where n = h.Len().