56 lines
1.0 KiB
Go
56 lines
1.0 KiB
Go
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package queue
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type (
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Queue struct {
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start, end *node
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length int
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}
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node struct {
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value interface{}
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next *node
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}
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)
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// Create a new queue
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func New() *Queue {
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return &Queue{nil,nil,0}
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}
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// Take the next item off the front of the queue
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func (this *Queue) Dequeue() interface{} {
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if this.length == 0 {
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return nil
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}
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n := this.start
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if this.length == 1 {
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this.start = nil
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this.end = nil
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} else {
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this.start = this.start.next
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}
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this.length--
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return n.value
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}
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// Put an item on the end of a queue
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func (this *Queue) Enqueue(value interface{}) {
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n := &node{value,nil}
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if this.length == 0 {
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this.start = n
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this.end = n
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} else {
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this.end.next = n
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this.end = n
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}
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this.length++
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}
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// Return the number of items in the queue
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func (this *Queue) Len() int {
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return this.length
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}
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// Return the first item in the queue without removing it
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func (this *Queue) Peek() interface{} {
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if this.length == 0 {
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return nil
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}
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return this.start.value
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}
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