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priority_queue_example
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| import ( | |
| "container/heap" | |
| ) | |
| type Event struct { | |
| Raw string | |
| Number uint64 | |
| MsgType int | |
| FromUserID uint64 | |
| ToUserID uint64 | |
| } | |
| type EventsMinHeap []*Event | |
| func (h EventsMinHeap) Len() int { | |
| return len(h) | |
| } | |
| func (h EventsMinHeap) Less(i, j int) bool { | |
| return h[i].Number < h[j].Number | |
| } | |
| func (h EventsMinHeap) Swap(i, j int) { | |
| h[i], h[j] = h[j], h[i] | |
| } | |
| func (h *EventsMinHeap) Push(x interface{}) { | |
| *h = append(*h, x.(*Event)) | |
| } | |
| func (h *EventsMinHeap) Pop() interface{} { | |
| old := *h | |
| tailIndex := old.Len() - 1 | |
| tail := old[tailIndex] | |
| old[tailIndex] = nil | |
| *h = old[:tailIndex] | |
| return tail | |
| } | |
| type Node struct { | |
| Val interface{} | |
| Next *Node | |
| Prev *Node | |
| } | |
| type BoundedFifoQueue struct { | |
| mx sync.RWMutex | |
| Head *Node | |
| Tail *Node | |
| MaxSize int | |
| count int | |
| } | |
| func NewBoundedQueue(maxSize int) *BoundedFifoQueue { | |
| return &BoundedFifoQueue{ | |
| MaxSize: maxSize, | |
| } | |
| } | |
| func (b *BoundedFifoQueue) PushBack(val interface{}) { | |
| b.mx.Lock() | |
| defer b.mx.Unlock() | |
| if b.count == b.MaxSize { | |
| oldHead := b.Head | |
| b.Head = oldHead.Next | |
| oldHead = nil | |
| b.count-- | |
| } | |
| newTail := &Node{Val: val, Prev: b.Tail} | |
| if b.count > 0 { | |
| oldTail := b.Tail | |
| oldTail.Next = newTail | |
| b.Tail = newTail | |
| } else { | |
| b.Head = newTail | |
| } | |
| b.Tail = newTail | |
| b.count++ | |
| } | |
| func (b *BoundedFifoQueue) PushFront(val interface{}) { | |
| b.mx.Lock() | |
| defer b.mx.Unlock() | |
| if b.count == b.MaxSize { | |
| oldTail := b.Tail | |
| b.Tail = oldTail.Prev | |
| oldTail = nil | |
| b.count-- | |
| } | |
| newHead := &Node{Val: val, Next: b.Head} | |
| if b.count > 0 { | |
| oldHead := b.Head | |
| oldHead.Prev = newHead | |
| } else { | |
| b.Tail = newHead | |
| } | |
| b.Head = newHead | |
| b.count++ | |
| } | |
| func (b *BoundedFifoQueue) Pop() interface{} { | |
| b.mx.Lock() | |
| defer b.mx.Unlock() | |
| if b.count > 0 { | |
| head := b.Head | |
| b.Head = head.Next | |
| val := head.Val | |
| head = nil | |
| b.count-- | |
| return val | |
| } | |
| return nil | |
| } | |
| func (b *BoundedFifoQueue) Front() interface{} { | |
| b.mx.RLock() | |
| defer b.mx.RUnlock() | |
| return b.Head.Val | |
| } | |
| func (b *BoundedFifoQueue) Back() interface{} { | |
| b.mx.RLock() | |
| defer b.mx.RUnlock() | |
| return b.Tail.Val | |
| } | |
| func (b *BoundedFifoQueue) Len() int { | |
| b.mx.RLock() | |
| defer b.mx.RUnlock() | |
| return b.count | |
| } | |
| type PriorityQueue struct { | |
| mx sync.RWMutex | |
| events *EventsMinHeap | |
| maxSize int | |
| } | |
| func NewPriorityQueue(maxSize int) *PriorityQueue { | |
| return &PriorityQueue{ | |
| events: new(EventsMinHeap), | |
| maxSize: maxSize, | |
| } | |
| } | |
| func (p *PriorityQueue) Push(event *Event) { | |
| p.mx.Lock() | |
| defer p.mx.Unlock() | |
| size := p.events.Len() | |
| if size == p.maxSize { | |
| heap.Pop(p.events) | |
| } | |
| heap.Push( | |
| p.events, | |
| event, | |
| ) | |
| } | |
| func (p *PriorityQueue) Pop() *Event { | |
| p.mx.Lock() | |
| defer p.mx.Unlock() | |
| if p.events.Len() == 0 { | |
| return nil | |
| } | |
| return heap.Pop(p.events).(*Event) | |
| } | |
| func (p *PriorityQueue) Len() int { | |
| p.mx.RLock() | |
| defer p.mx.RUnlock() | |
| return p.events.Len() | |
| } |
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