Java是一門(mén)廣泛應(yīng)用于軟件開(kāi)發(fā)和網(wǎng)絡(luò)編程的編程語(yǔ)言，很多開(kāi)發(fā)人員都會(huì)選擇使用Java來(lái)實(shí)現(xiàn)一個(gè)隊(duì)列數(shù)據(jù)結(jié)構(gòu)。隊(duì)列是一種數(shù)據(jù)結(jié)構(gòu)，類(lèi)似于現(xiàn)實(shí)生活中的排隊(duì)，它遵循先進(jìn)先出的原則。Java中可以使用數(shù)組和鏈表來(lái)實(shí)現(xiàn)一個(gè)隊(duì)列。

使用數(shù)組實(shí)現(xiàn)隊(duì)列：

public class ArrayQueue {
private int[] queue;
private int head;
private int tail;
private int size;
private int capacity;
public ArrayQueue(int capacity) {
this.queue = new int[capacity];
this.head = 0;
this.tail = 0;
this.size = 0;
this.capacity = capacity;
}
public void enqueue(int item) {
if (size == capacity) {
throw new RuntimeException("Queue is full");
}
queue[tail] = item;
tail = (tail + 1) % capacity;
size++;
}
public int dequeue() {
if (size == 0) {
throw new RuntimeException("Queue is empty");
}
int item = queue[head];
head = (head + 1) % capacity;
size--;
return item;
}
public boolean isEmpty() {
return size == 0;
}
}

使用鏈表實(shí)現(xiàn)隊(duì)列：

public class LinkedListQueue {
private ListNode head;
private ListNode tail;
private int size;
public LinkedListQueue() {
this.head = null;
this.tail = null;
this.size = 0;
}
public void enqueue(int item) {
ListNode newNode = new ListNode(item);
if (tail == null) {
head = newNode;
tail = newNode;
} else {
tail.next = newNode;
tail = newNode;
}
size++;
}
public int dequeue() {
if (head == null) {
throw new RuntimeException("Queue is empty");
}
int item = head.val;
head = head.next;
if (head == null) {
tail = null;
}
size--;
return item;
}
public boolean isEmpty() {
return head == null;
}
private static class ListNode {
private int val;
private ListNode next;
public ListNode(int val) {
this.val = val;
this.next = null;
}
}
}

通過(guò)數(shù)組和鏈表來(lái)實(shí)現(xiàn)一個(gè)隊(duì)列數(shù)據(jù)結(jié)構(gòu)，可以方便地進(jìn)行插入和刪除操作，并且可以保證數(shù)據(jù)在隊(duì)列中的先后順序。