Queue by Java

Author: KevinLvLight

LinkedQueue.java

@@ -0,0 +1,35 @@
+public class LinkedQueue{
+    //定义一个节点类
+    private class Node{
+        String value;
+        Node next;
+    }
+
+    private int size = 0;
+    private Node head;
+    private Node tail;
+
+    public LinkedQueue(){};
+
+    public boolean enQueue(String item){
+        Node newNode = new Node();
+        newNode.value = item;
+        
+        if(size == 0) head = newNode;
+        else tail.next = newNode;
+
+        tail = newNode;
+        size++;
+        return true;
+    }
+
+    public String deQueue(){
+        String res = null;
+        if(size == 0) return res;
+        if(size == 1) tail = null;
+        res = head.value;
+        head = head.next;
+        size--;
+        return res;
+    }
+}

LoopArrayQueue.java

@@ -0,0 +1,40 @@
+/**
+ * 循环队列
+ * 数组实现
+ * 队列空：head == tail
+ * 队列满：(tail + 1) % n == head
+ * tail所指向的位置实际没有存储数据
+ */
+
+public class LoopArrayQueue{
+    private String items[];//存储数据的数组
+
+    private int n;
+    private int size = 0;//记录数组容量
+
+    private int head = 0;
+    private int tail = 0;
+
+    public LoopArrayQueue(int capacity){
+        items = new String[capacity];
+        n = capacity;
+    }
+
+    public boolean enQueue(String item){
+        if((tail + 1) % n == head) return false;
+        items[tail] = item;
+        tail = (tail + 1) % n;
+        size++;
+        return true;
+    }
+
+    public String deQueue(){
+        String res = null;
+        if(head == tail) return res;
+        res = items[head];
+        head = (head + 1) % n;
+        size--;
+        return res;
+    }
+
+}