135 lines
3.3 KiB
C++
135 lines
3.3 KiB
C++
/*
|
|
* File: array_queue.cpp
|
|
* Created Time: 2022-11-25
|
|
* Author: Krahets (krahets@163.com)
|
|
*/
|
|
|
|
#include "../include/include.hpp"
|
|
|
|
/* 基于环形数组实现的队列 */
|
|
class ArrayQueue {
|
|
private:
|
|
int *nums; // 用于存储队列元素的数组
|
|
int cap; // 队列容量
|
|
int front = 0; // 头指针，指向队首
|
|
int rear = 0; // 尾指针，指向队尾 + 1
|
|
|
|
public:
|
|
ArrayQueue(int capacity) {
|
|
// 初始化数组
|
|
cap = capacity;
|
|
nums = new int[capacity];
|
|
}
|
|
|
|
/* 获取队列的容量 */
|
|
int capacity() {
|
|
return cap;
|
|
}
|
|
|
|
/* 获取队列的长度 */
|
|
int size() {
|
|
// 由于将数组看作为环形，可能 rear < front ，因此需要取余数
|
|
return (capacity() + rear - front) % capacity();
|
|
}
|
|
|
|
/* 判断队列是否为空 */
|
|
bool empty() {
|
|
return rear - front == 0;
|
|
}
|
|
|
|
/* 入队 */
|
|
void offer(int num) {
|
|
if (size() == capacity()) {
|
|
cout << "队列已满" << endl;
|
|
return;
|
|
}
|
|
// 尾结点后添加 num
|
|
nums[rear] = num;
|
|
// 尾指针向后移动一位，越过尾部后返回到数组头部
|
|
rear = (rear + 1) % capacity();
|
|
}
|
|
|
|
/* 出队 */
|
|
int poll() {
|
|
int num = peek();
|
|
// 队头指针向后移动一位，若越过尾部则返回到数组头部
|
|
front = (front + 1) % capacity();
|
|
return num;
|
|
}
|
|
|
|
/* 访问队首元素 */
|
|
int peek() {
|
|
// 删除头结点
|
|
if (empty())
|
|
throw out_of_range("队列为空");
|
|
return nums[front];
|
|
}
|
|
|
|
/* 访问指定索引元素 */
|
|
int get(int index) {
|
|
if (index >= size())
|
|
throw out_of_range("索引越界");
|
|
return nums[(front + index) % capacity()];
|
|
}
|
|
|
|
/* 将数组转化为 Vector 并返回 */
|
|
vector<int> toVector() {
|
|
int siz = size();
|
|
int cap = capacity();
|
|
// 仅转换有效长度范围内的列表元素
|
|
vector<int> arr(siz);
|
|
for (int i = 0, j = front; i < siz; i++, j++) {
|
|
arr[i] = nums[j % cap];
|
|
}
|
|
return arr;
|
|
}
|
|
};
|
|
|
|
|
|
/* Driver Code */
|
|
int main() {
|
|
/* 初始化队列 */
|
|
int capacity = 10;
|
|
ArrayQueue* queue = new ArrayQueue(capacity);
|
|
|
|
/* 元素入队 */
|
|
queue->offer(1);
|
|
queue->offer(3);
|
|
queue->offer(2);
|
|
queue->offer(5);
|
|
queue->offer(4);
|
|
cout << "队列 queue = ";
|
|
PrintUtil::printVector(queue->toVector());
|
|
|
|
/* 访问队首元素 */
|
|
int peek = queue->peek();
|
|
cout << "队首元素 peek = " << peek << endl;
|
|
|
|
/* 访问指定索引元素 */
|
|
int num = queue->get(2);
|
|
cout << "队列第 3 个元素为 num = " << num << endl;
|
|
|
|
/* 元素出队 */
|
|
int poll = queue->poll();
|
|
cout << "出队元素 poll = " << poll << "，出队后 queue = ";
|
|
PrintUtil::printVector(queue->toVector());
|
|
|
|
/* 获取队列的长度 */
|
|
int size = queue->size();
|
|
cout << "队列长度 size = " << size << endl;
|
|
|
|
/* 判断队列是否为空 */
|
|
bool empty = queue->empty();
|
|
cout << "队列是否为空 = " << empty << endl;
|
|
|
|
/* 测试环形数组 */
|
|
for (int i = 0; i < 10; i++) {
|
|
queue->offer(i);
|
|
queue->poll();
|
|
cout << "第 " << i << " 轮入队 + 出队后 queue = ";
|
|
PrintUtil::printVector(queue->toVector());
|
|
}
|
|
|
|
return 0;
|
|
}
|