数据结构在Java中的实践：链表、队列的实现示例

原创 ╰+哭是因爲堅強的太久メ 2024-10-18 07:03 26阅读 0赞

在Java中，我们可以使用基本的数据类型或者一些特定的类来实现各种数据结构。这里我们将重点介绍如何实现链表和队列这两种数据结构。

1. 链表（LinkedList）：

```java
import java.util.LinkedList;

// Node class for creating a linked list node
class Node {
    int data;
    Node next;

// Constructor to create a new node
    Node(int data) {
        this.data = data;
        this.next = null;
    }
}

// LinkedList class implementation
public class LinkedList {
    Node head;

// Method to add a new node at the beginning of the list
    public void appendNode(int data) {
        Node newNode = new Node(data);

if (head == null) { // If list is empty, set the new node as head
            head = newNode;
        } else {
            newNode.next = head; // Add next pointer for the new node to be linked to the existing head node
            head = newNode; // Update head node to point to the new node
        }
    }

// Method to print the elements of the list in reverse order
    public void displayListInReverse() {
        Node currentNode = head;

while (currentNode != null) {
            System.out.print(currentNode.data + " -> "); // Print the current node data along with arrow
            currentNode = currentNode.next;
        }

// If list is empty, print "Empty List"
        if (head == null) {
            System.out.println("Empty List");
        }
    }
}
```

2. 队列（Queue）：

在Java中，可以使用`PriorityQueue`来实现一个基于优先级的队列。这里以普通无序队列为例：

```java
import java.util.LinkedList;
import java.util.Queue;

public class QueueExample {
    // Queue implementation using LinkedList
    private Queue<Integer> queue = new LinkedList<>();

// Method to add an element to the end of the queue
    public void enqueue(int data) {
        queue.add(data);
    }

// Method to remove and return the first (head) element from the queue
    public int dequeue() {
        if (queue.isEmpty()) { // If queue is empty, throw exception
            throw new IllegalStateException("Queue underflow");
        }
        return queue.remove(0); // Remove the first element (index 0) and return it
    }

// Method to check if the queue is empty
    public boolean isEmpty() {
        return queue.isEmpty();
    }
}
```

以上就是链表和队列在Java中实现的基本示例。