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@ -0,0 +1,87 @@ |
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package common |
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import ( |
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"container/heap" |
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) |
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type Heap struct { |
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pq priorityQueue |
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} |
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func NewHeap() *Heap { |
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return &Heap{pq:make([]*pqItem, 0)} |
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} |
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func (h *Heap) Len() int { |
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return len(h.pq) |
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} |
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func (h *Heap) Push(value interface{}, priority int) { |
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heap.Push(&h.pq, &pqItem{value:value, priority:priority}) |
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} |
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func (h *Heap) Pop() interface{} { |
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item := heap.Pop(&h.pq).(*pqItem) |
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return item.value |
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} |
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/* |
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func main() { |
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h := NewHeap() |
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h.Push(String("msg1"), 1) |
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h.Push(String("msg3"), 3) |
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h.Push(String("msg2"), 2) |
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fmt.Println(h.Pop()) |
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fmt.Println(h.Pop()) |
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fmt.Println(h.Pop()) |
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} |
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*/ |
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///////////////////////
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// From: http://golang.org/pkg/container/heap/#example__priorityQueue
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type pqItem struct { |
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value interface{} |
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priority int |
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index int |
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} |
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type priorityQueue []*pqItem |
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func (pq priorityQueue) Len() int { return len(pq) } |
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func (pq priorityQueue) Less(i, j int) bool { |
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return pq[i].priority < pq[j].priority |
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} |
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func (pq priorityQueue) Swap(i, j int) { |
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pq[i], pq[j] = pq[j], pq[i] |
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pq[i].index = i |
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pq[j].index = j |
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} |
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func (pq *priorityQueue) Push(x interface{}) { |
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n := len(*pq) |
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item := x.(*pqItem) |
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item.index = n |
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*pq = append(*pq, item) |
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} |
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func (pq *priorityQueue) Pop() interface{} { |
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old := *pq |
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n := len(old) |
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item := old[n-1] |
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item.index = -1 // for safety
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*pq = old[0 : n-1] |
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return item |
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} |
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func (pq *priorityQueue) Update(item *pqItem, value ByteSlice, priority int) { |
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heap.Remove(pq, item.index) |
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item.value = value |
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item.priority = priority |
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heap.Push(pq, item) |
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} |
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