Heap
A heap is a Tree data structure that is complete, or every level is full.
- Max heap: A heap where the value of the node is the greatest value in that node’s sub-tree. This must be true for all nodes in the heap
- Min heap: A heap where the value of the node in the smallest value in that node’s sub-tree. This must be true for all nodes in the heap
Heaps can be valuable when it is necessary to remove nodes with either the highest or lowest priority or when inserts are mixed with removals of the root node.
| Operation | Big-O |
|---|---|
| Find max/min | O(1) |
| Insert | O(log(n)) |
| Remove | O(log(n)) |
| Create | O(n) |
Examples
go
Using the heap package
type Heap []int
func (h Heap) Len() int {
return len(h)
}
func (h Heap) Less(i int, j int) bool {
return h[i] < h[j]
}
func (h Heap) Swap(i int, j int) {
h[i], h[j] = h[j], h[i]
}
func (h *Heap) Push(x any) {
*h = append(*h, x.(int))
}
func (h *Heap) Pop() any {
old := *h
n := len(old)
x := old[n-1]
*h = old[0 : n-1]
return x
}