Java 队列

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循环队列：

package com.darren.test.datastructure;/** * 此队列为循环队列。 不设标志位，少使用一个存储空间，约定队头指针在队尾指针的下一位时作为满状态。 * 此时如果队头指针和队尾指针相等，作为空状态。 *  * @author Darren.Zhang */public class Queue {    private int maxSize;    private int[] data;    private int front;    private int end;    public Queue(int size) {        this.maxSize = size;        data = new int[size];    }    /**     * 添加数据，并移动指针     *      * @param value     */    public void addValue(int value) {        if ((end + 1) % maxSize == front) {            System.out.println("队列已满！");        } else {            data[end] = value;            // 指针后移一位            end = (end + 1) % maxSize;        }    }    /**     * 取出数据，并移动指针     *      * @return     */    public Integer getValue() {        Integer value = null;        if (front == end) {            System.out.println("队列已空！");        } else {            value = data[front];            // 指针后移一位            front = (front + 1) % maxSize;        }        return value;    }    /**     * 查看数据，不移动指针     *      * @return     */    public Integer peek() {        Integer value = null;        if (front == end) {            System.out.println("队列已空！");        } else {            value = data[front];        }        return value;    }    /**     * 计算队列大小     *      * @return     */    public int size() {        int size = (end - front + maxSize) % maxSize;        return size;    }}

循环队列测试：

package com.darren.test.datastructure;public class QueueTest {    public static void main(String[] args) {        Queue queue = new Queue(5);        queue.addValue(5);        queue.addValue(4);        queue.addValue(3);        queue.addValue(2);        queue.addValue(1);        // test1(queue);        // test2(queue);        test3(queue);    }    /**     * 测试方式一     *      * @param queue     */    private static void test1(Queue queue) {        System.out.println("测试方式一");        while (true) {            Integer value = queue.getValue();            if (value != null) {                System.out.println(value);            } else {                break;            }        }    }    /**     * 测试方式二     *      * @param queue     */    private static void test2(Queue queue) {        System.out.println("测试方式二");        int size = queue.size();        for (int i = 0; i < size; i++) {            System.out.println(queue.getValue());        }    }    /**     * 测试方式三     *      * @param queue     */    private static void test3(Queue queue) {        System.out.println("测试方式三");        while (queue.peek() != null) {            System.out.println(queue.getValue());        }    }}

优先级队列：

package com.darren.test.datastructure;/** * 队头小队尾大 *  * @author Darren.Zhang */public class PriorityQueue {    private int maxSize;    private int[] data;    private int length;    public PriorityQueue(int size) {        this.maxSize = size;        data = new int[size];    }    public void addValue(int value) {        if (length == maxSize) {            System.out.println("优先队列已满！");        } else if (length == 0) {            data[length++] = value;        } else {            int i = length - 1;            for (; i >= 0; i--) {                if (value > data[i]) {                    data[i + 1] = data[i];                } else {                    break;                }            }            data[i + 1] = value;            length++;        }    }    public Integer getValue() {        Integer value = null;        if (length == 0) {            System.out.println("优先队列已空！");        } else {            value = data[--length];        }        return value;    }    public Integer peek() {        Integer value = null;        if (length == 0) {            System.out.println("优先队列已空！");        } else {            value = data[length - 1];        }        return value;    }    public int size() {        return length;    }}

优先级队列测试：

package com.darren.test.datastructure;public class PriorityQueueTest {    public static void main(String[] args) {        PriorityQueue priorityQueue = new PriorityQueue(5);        priorityQueue.addValue(4);        priorityQueue.addValue(5);        priorityQueue.addValue(3);        priorityQueue.addValue(1);        priorityQueue.addValue(2);        priorityQueue.addValue(0);        // test1(priorityQueue);        // test2(priorityQueue);        test3(priorityQueue);    }    /**     * 测试方式一     *      * @param priorityQueue     */    private static void test1(PriorityQueue priorityQueue) {        System.out.println("测试方式一");        while (true) {            Integer value = priorityQueue.getValue();            if (value != null) {                System.out.println(value);            } else {                break;            }        }    }    /**     * 测试方式二     *      * @param priorityQueue     */    private static void test2(PriorityQueue priorityQueue) {        System.out.println("测试方式二");        int size = priorityQueue.size();        for (int i = 0; i < size; i++) {            System.out.println(priorityQueue.getValue());        }    }    /**     * 测试方式三     *      * @param priorityQueue     */    private static void test3(PriorityQueue priorityQueue) {        System.out.println("测试方式三");        while (priorityQueue.peek() != null) {            System.out.println(priorityQueue.getValue());        }    }}

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