79 lines
2.3 KiB
Go
79 lines
2.3 KiB
Go
// CookieJar - A contestant's algorithm toolbox
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// Copyright (c) 2013 Peter Szilagyi. All rights reserved.
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//
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// CookieJar is dual licensed: use of this source code is governed by a BSD
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// license that can be found in the LICENSE file. Alternatively, the CookieJar
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// toolbox may be used in accordance with the terms and conditions contained
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// in a signed written agreement between you and the author(s).
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// This is a duplicated and slightly modified version of "gopkg.in/karalabe/cookiejar.v2/collections/prque".
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// Package prque implements a priority queue data structure supporting arbitrary
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// value types and int64 priorities.
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//
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// If you would like to use a min-priority queue, simply negate the priorities.
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//
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// Internally the queue is based on the standard heap package working on a
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// sortable version of the block based stack.
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package prque
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import (
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"container/heap"
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)
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// Priority queue data structure.
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type Prque struct {
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cont *sstack
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}
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// New creates a new priority queue.
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func New(setIndex SetIndexCallback) *Prque {
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return &Prque{newSstack(setIndex)}
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}
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// Pushes a value with a given priority into the queue, expanding if necessary.
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func (p *Prque) Push(data interface{}, priority int64) {
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heap.Push(p.cont, &item{data, priority})
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}
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// Peek returns the value with the greates priority but does not pop it off.
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func (p *Prque) Peek() (interface{}, int64) {
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item := p.cont.blocks[0][0]
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return item.value, item.priority
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}
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// Pops the value with the greates priority off the stack and returns it.
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// Currently no shrinking is done.
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func (p *Prque) Pop() (interface{}, int64) {
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item := heap.Pop(p.cont).(*item)
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return item.value, item.priority
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}
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// Pops only the item from the queue, dropping the associated priority value.
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func (p *Prque) PopItem() interface{} {
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return heap.Pop(p.cont).(*item).value
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}
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// Remove removes the element with the given index.
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func (p *Prque) Remove(i int) interface{} {
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if i < 0 {
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return nil
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}
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return heap.Remove(p.cont, i)
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}
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// Checks whether the priority queue is empty.
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func (p *Prque) Empty() bool {
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return p.cont.Len() == 0
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}
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// Returns the number of element in the priority queue.
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func (p *Prque) Size() int {
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return p.cont.Len()
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}
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// Clears the contents of the priority queue.
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func (p *Prque) Reset() {
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*p = *New(p.cont.setIndex)
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}
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