130 lines
2.8 KiB
C++
130 lines
2.8 KiB
C++
/**
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* File: array_queue.cpp
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* Created Time: 2022-11-25
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* Author: krahets (krahets@163.com)
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*/
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#include "../utils/common.hpp"
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/* 基于环形数组实现的队列 */
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class ArrayQueue {
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private:
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int *nums; // 用于存储队列元素的数组
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int front; // 队首指针，指向队首元素
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int queSize; // 队列长度
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int queCapacity; // 队列容量
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public:
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ArrayQueue(int capacity) {
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// 初始化数组
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nums = new int[capacity];
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queCapacity = capacity;
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front = queSize = 0;
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}
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~ArrayQueue() {
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delete[] nums;
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}
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/* 获取队列的容量 */
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int capacity() {
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return queCapacity;
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}
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/* 获取队列的长度 */
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int size() {
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return queSize;
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}
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/* 判断队列是否为空 */
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bool isEmpty() {
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return size() == 0;
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}
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/* 入队 */
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void push(int num) {
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if (queSize == queCapacity) {
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cout << "队列已满" << endl;
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return;
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}
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// 计算队尾指针，指向队尾索引 + 1
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// 通过取余操作实现 rear 越过数组尾部后回到头部
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int rear = (front + queSize) % queCapacity;
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// 将 num 添加至队尾
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nums[rear] = num;
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queSize++;
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}
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/* 出队 */
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int pop() {
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int num = peek();
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// 队首指针向后移动一位，若越过尾部，则返回到数组头部
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front = (front + 1) % queCapacity;
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queSize--;
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return num;
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}
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/* 访问队首元素 */
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int peek() {
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if (isEmpty())
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throw out_of_range("队列为空");
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return nums[front];
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}
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/* 将数组转化为 Vector 并返回 */
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vector<int> toVector() {
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// 仅转换有效长度范围内的列表元素
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vector<int> arr(queSize);
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for (int i = 0, j = front; i < queSize; i++, j++) {
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arr[i] = nums[j % queCapacity];
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}
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return arr;
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}
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};
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/* Driver Code */
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int main() {
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/* 初始化队列 */
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int capacity = 10;
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ArrayQueue *queue = new ArrayQueue(capacity);
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/* 元素入队 */
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queue->push(1);
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queue->push(3);
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queue->push(2);
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queue->push(5);
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queue->push(4);
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cout << "队列 queue = ";
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printVector(queue->toVector());
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/* 访问队首元素 */
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int peek = queue->peek();
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cout << "队首元素 peek = " << peek << endl;
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/* 元素出队 */
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peek = queue->pop();
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cout << "出队元素 pop = " << peek << "，出队后 queue = ";
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printVector(queue->toVector());
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/* 获取队列的长度 */
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int size = queue->size();
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cout << "队列长度 size = " << size << endl;
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/* 判断队列是否为空 */
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bool empty = queue->isEmpty();
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cout << "队列是否为空 = " << empty << endl;
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/* 测试环形数组 */
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for (int i = 0; i < 10; i++) {
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queue->push(i);
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queue->pop();
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cout << "第 " << i << " 轮入队 + 出队后 queue = ";
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printVector(queue->toVector());
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}
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// 释放内存
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delete queue;
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return 0;
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}
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