93 lines
2.0 KiB
Go
93 lines
2.0 KiB
Go
// File: array_queue.go
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// Created Time: 2022-11-28
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// Author: Reanon (793584285@qq.com)
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package chapter_stack_and_queue
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import (
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"fmt"
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"strings"
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)
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// ArrayQueue 基于环形数组实现的队列, 不支持扩容
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type ArrayQueue struct {
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data []any // 用于存储队列元素的数组
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capacity int // 队列容量（即最多容量的元素个数）
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head int // 头指针，指向队首
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tail int // 尾指针，指向队尾 + 1
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}
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// NewArrayQueue 基于环形数组实现的队列
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func NewArrayQueue(capacity int) *ArrayQueue {
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return &ArrayQueue{
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data: make([]any, capacity),
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capacity: capacity,
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head: 0,
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tail: 0,
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}
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}
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// Size 获取队列的长度
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func (q *ArrayQueue) Size() int {
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size := (q.capacity + q.tail - q.head) % q.capacity
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return size
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}
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// IsEmpty 判断队列是否为空
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func (q *ArrayQueue) IsEmpty() bool {
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return q.tail-q.head == 0
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}
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// Offer 入队
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func (q *ArrayQueue) Offer(v any) {
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// 当 tail == capacity 表示队列已满
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if q.Size() == q.capacity {
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return
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}
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// 尾结点后添加
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q.data[q.tail] = v
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// 尾指针向后移动一位，越过尾部后返回到数组头部
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q.tail = (q.tail + 1) % q.capacity
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}
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// Poll 出队
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func (q *ArrayQueue) Poll() any {
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if q.IsEmpty() {
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return nil
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}
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v := q.data[q.head]
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// 队头指针向后移动，越过尾部后返回到数组头部
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q.head = (q.head + 1) % q.capacity
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return v
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}
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// Peek 访问队首元素
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func (q *ArrayQueue) Peek() any {
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if q.IsEmpty() {
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return nil
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}
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v := q.data[q.head]
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return v
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}
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func (q *ArrayQueue) Print() {
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fmt.Println(q.toString())
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}
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// toString 通过字符串的方式输出
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func (q *ArrayQueue) toString() string {
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// 为空时
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if q.IsEmpty() {
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return "empty items"
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}
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var builder strings.Builder
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size := q.Size()
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str := fmt.Sprintf("%+v", q.data[q.head])
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for i := 1; i < size; i++ {
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builder.WriteString(str + " -> ")
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str = fmt.Sprintf("%+v", q.data[(i+q.head)%q.capacity])
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}
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builder.WriteString(str)
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return builder.String()
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}
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