數據結構-08 隊列(循環隊列)

1、主要代碼數據結構-07 隊列()代碼：

	/**
	 * 添加數據，從隊尾插入
	 */
	public void insert(long value){
		//當end指到隊列結尾時，再調整指到初始位置
		if(end == arr.length - 1){
			end = -1;
		}
		arr[++end] = value;
		elements++;
	}
	
	/**
	 * 刪除數據，從隊頭刪除
	 */
	public long remove(){
		long value = arr[front++];
		//當front指到隊列結尾時，再調整指到初始位置
		if(front == arr.length){
			front = 0;
		}
		elements--;
		return value;
	}

2、完整代碼：

package org.gzw.ch03;
/**
 * 隊列
 */
public class MyCycleQueue {
	//底層試用數組
	private long[] arr;
	//有效數據的長度
	private int elements;
	//對頭
	private int front;
	//隊尾
	private int end;

	/**
	 * 默認無參構造
	 */
	public MyCycleQueue(){
		arr = new long[10];
		elements = 0;
		front = 0;
		end = -1;
	}
	
	/**
	 * 帶參數的構造方法
	 */
	public MyCycleQueue(int maxsize){
		arr = new long[maxsize];
		elements = 0;
		front = 0;
		end = -1;
	}
	
	/**
	 * 添加數據，從隊尾插入
	 */
	public void insert(long value){
		//當end指到隊列結尾時，再調整指到初始位置
		if(end == arr.length - 1){
			end = -1;
		}
		arr[++end] = value;
		elements++;
	}
	
	/**
	 * 刪除數據，從隊頭刪除
	 */
	public long remove(){
		long value = arr[front++];
		//當front指到隊列結尾時，再調整指到初始位置
		if(front == arr.length){
			front = 0;
		}
		elements--;
		return value;
	}
	
	/**
	 * 查看數據，從隊頭查看
	 */
	public long peek(){
		return arr[front];
	}
	
	/**
	 * 判斷是否爲空
	 */
	public boolean isEmpty(){
		return elements == 0;
	}
	
	/**
	 * 判斷是否滿了
	 */
	public boolean isFull(){
		//return (end - front) == arr.length;
		return elements == arr.length;
	}
}

3、測試：

package org.gzw.ch03;

public class TestMyCycleQueue {

	public static void main(String[] args) {
		MyCycleQueue myCycleQueue = new MyCycleQueue(4);
		myCycleQueue.insert(23);
		myCycleQueue.insert(45);
		myCycleQueue.insert(13);
		myCycleQueue.insert(1);
		
		System.out.println(myCycleQueue.isEmpty());
		System.out.println(myCycleQueue.isFull());
		System.out.println(myCycleQueue.peek());
		System.out.println(myCycleQueue.peek());
		
		while(!myCycleQueue.isEmpty()){
			System.out.print(myCycleQueue.remove() + ", ");
		}
		System.out.println();
		System.out.println(myCycleQueue.isFull());
		System.out.println(myCycleQueue.isEmpty());
		System.out.println(myCycleQueue.peek());
		
		System.out.println("-----------------------------");
		
		//這裏不會報錯，原因是end位置在隊列結尾時，會在指向初始位置
		myCycleQueue.insert(21);
		System.out.println(myCycleQueue.peek());
		myCycleQueue.insert(22);
		myCycleQueue.insert(23);
		myCycleQueue.insert(24);
		
		while(!myCycleQueue.isEmpty()){
			System.out.print(myCycleQueue.remove() + ", ");
		}
		
		System.out.println();
		System.out.println(myCycleQueue.peek());
	}

}

4、運行結果：

false
true
23
23
23, 45, 13, 1, 
false
true
23
-----------------------------
21
21, 22, 23, 24, 
21