I'm trying to implement a priority queue based on the example provided in the documentation. Docs: priorityQueue
In short it looks like this (not everything is included):
package pq
type Item struct {
container interface{}
priority int
index int
}
type PriorityQueue []*Item
func NewItem(value interface{}, prio int) *Item {
return &Item {container: value, priority: prio}
}
func (pq PriorityQueue) Len() int {
return len(pq)
}
func (pq PriorityQueue) Less(i, j int) bool {
return pq[i].priority > pq[j].priority
}
func (pq *PriorityQueue) Swap(i, j int) {
(*pq)[i], (*pq)[j] = (*pq)[j], (*pq)[i]
(*pq)[i].index = i
(*pq)[j].index = j
}
func (pq PriorityQueue) Push(x interface{}) {
fmt.Printf("adr: %p
", &pq)
n := len(pq)
item := x.(*Item)
item.index = n
pq = append(pq, item)
}
func (pq *PriorityQueue) Pop() interface{} {
old := *pq
n := len(old)
itm := old[n - 1]
itm.index = -1
*pq = old[0 : n-1]
return itm.container
}
The main.go
file:
func main() {
q := pq.PriorityQueue{}
heap.Init(q)
fmt.Printf("
Adr: %p
", &q)
q.Push(pq.NewItem("h", 2))
for i := 0; i < 5; i++ {
item := pq.NewItem("test", i * 13 % 7)
heap.Push(q, item)
}
for q.Len() > 0 {
fmt.Println("Item: " + heap.Pop(q).(string))
}
}
As you can see when comparing to the example I do not use pointers since doing that will give me a compile error telling me that my priority queue does not implement the interface properly.
This leaves me with the following problem when I do:
heap.Push(q, item)
that the item is not appended to the queue.
I've tried to write out the queues pointer address and it shows different addresses. This explains why it does not work, but souldn't slices not be reference types a long with maps?
And more specificly: How do i solve my problem?
Hope you can help!
Edit: Added full code and error: cannot use q (type pq.PriorityQueue) as type heap.Interface in function argument: pq.PriorityQueue does not implement heap.Interface (Pop method has pointer receiver)