hello-algo/codes/csharp/chapter_stack_and_queue/array_deque.cs

175 lines
5.1 KiB
Java

/**
* File: array_deque.cs
* Created Time: 2023-03-08
* Author: hpstory (hpstory1024@163.com)
*/
using NUnit.Framework;
namespace hello_algo.chapter_stack_and_queue
{
/* 基于环形数组实现的双向队列 */
public class ArrayDeque
{
private readonly int[] nums; // 用于存储双向队列元素的数组
private int front; // 队首指针,指向队首元素
private int queSize; // 双向队列长度
/* 构造方法 */
public ArrayDeque(int capacity)
{
this.nums = new int[capacity];
front = queSize = 0;
}
/* 获取双向队列的容量 */
public int capacity()
{
return nums.Length;
}
/* 获取双向队列的长度 */
public int size()
{
return queSize;
}
/* 判断双向队列是否为空 */
public bool isEmpty()
{
return queSize == 0;
}
/* 计算环形数组索引 */
private int index(int i)
{
// 通过取余操作实现数组首尾相连
// 当 i 越过数组尾部后,回到头部
// 当 i 越过数组头部后,回到尾部
return (i + capacity()) % capacity();
}
/* 队首入队 */
public void pushFirst(int num)
{
if (queSize == capacity())
{
Console.WriteLine("双向队列已满");
return;
}
// 队首指针向左移动一位
// 通过取余操作,实现 front 越过数组头部后回到尾部
front = index(front - 1);
// 将 num 添加至队首
nums[front] = num;
queSize++;
}
/* 队尾入队 */
public void pushLast(int num)
{
if (queSize == capacity())
{
Console.WriteLine("双向队列已满");
return;
}
// 计算尾指针,指向队尾索引 + 1
int rear = index(front + queSize);
// 将 num 添加至队尾
nums[rear] = num;
queSize++;
}
/* 队首出队 */
public int popFirst()
{
int num = peekFirst();
// 队首指针向后移动一位
front = index(front + 1);
queSize--;
return num;
}
/* 队尾出队 */
public int popLast()
{
int num = peekLast();
queSize--;
return num;
}
/* 访问队首元素 */
public int peekFirst()
{
if (isEmpty())
{
throw new InvalidOperationException();
}
return nums[front];
}
/* 访问队尾元素 */
public int peekLast()
{
if (isEmpty())
{
throw new InvalidOperationException();
}
// 计算尾元素索引
int last = index(front + queSize - 1);
return nums[last];
}
/* 返回数组用于打印 */
public int[] toArray()
{
// 仅转换有效长度范围内的列表元素
int[] res = new int[queSize];
for (int i = 0, j = front; i < queSize; i++, j++)
{
res[i] = nums[index(j)];
}
return res;
}
}
public class array_deque
{
[Test]
public void Test()
{
/* 初始化双向队列 */
ArrayDeque deque = new ArrayDeque(10);
deque.pushLast(3);
deque.pushLast(2);
deque.pushLast(5);
Console.WriteLine("双向队列 deque = " + string.Join(" ", deque.toArray()));
/* 访问元素 */
int peekFirst = deque.peekFirst();
Console.WriteLine("队首元素 peekFirst = " + peekFirst);
int peekLast = deque.peekLast();
Console.WriteLine("队尾元素 peekLast = " + peekLast);
/* 元素入队 */
deque.pushLast(4);
Console.WriteLine("元素 4 队尾入队后 deque = " + string.Join(" ", deque.toArray()));
deque.pushFirst(1);
Console.WriteLine("元素 1 队首入队后 deque = " + string.Join(" ", deque.toArray()));
/* 元素出队 */
int popLast = deque.popLast();
Console.WriteLine("队尾出队元素 = " + popLast + ",队尾出队后 deque = " + string.Join(" ", deque.toArray()));
int popFirst = deque.popFirst();
Console.WriteLine("队首出队元素 = " + popFirst + ",队首出队后 deque = " + string.Join(" ", deque.toArray()));
/* 获取双向队列的长度 */
int size = deque.size();
Console.WriteLine("双向队列长度 size = " + size);
/* 判断双向队列是否为空 */
bool isEmpty = deque.isEmpty();
Console.WriteLine("双向队列是否为空 = " + isEmpty);
}
}
}