3、队列

1、队列的基本实现

public class MyQueue01 {    //数组    private int[] array;    //数组的最大长度    private int maxSize;    //队列的头    private int head;    //队列的尾    private int tail;    //有效数据的长度    private int elems;    public MyQueue01(int size){        this.maxSize = size;        array = new int[size];        head = 0;        tail = -1;        elems = 0;    }    //插入数据    public void insert(int value){        elems++;        array[++tail] = value;    }    //删除数据    public int remove(){        elems--;        return array[head++];    }    //是否已满    public boolean isFull(){        return (elems == (maxSize-1));    }    //是否为空    public boolean isEmpty(){        return elems==0;    }    //返回有效的长度    public int getSize(){        return elems;    }}

测试：

public class TestMyQueue01 {    public static void main(String[] args) {        MyQueue01 myQueue01 = new MyQueue01(5);        if(!myQueue01.isFull()){            myQueue01.insert(1);            myQueue01.insert(2);            myQueue01.insert(3);            myQueue01.insert(4);            myQueue01.insert(5);        }        while (!myQueue01.isEmpty()){            System.out.println(myQueue01.remove());        }        // 不能再插入了，因为已经满了，头跟尾都已经到数组的最后了        // myQueue01.insert(6);    }}

2、循环队列的实现

public class MyQueue02 {    //数组    private int[] array;    //数组的最大长度    private int maxSize;    //队列的头    private int head;    //队列的尾    private int tail;    //有效数据的长度    private int elems;    public MyQueue02(int size){        this.maxSize = size;        array = new int[size];        head = 0;        tail = -1;        elems = 0;    }    //插入数据    public void insert(int value){        //判断尾指针是否已经到队列的数据尾部，如果到了，就回到-1的地方        if(tail == maxSize-1){            tail = -1;        }        elems++;        array[++tail] = value;    }    //删除数据    public int remove(){        int tmp = array[head++];        if(head == maxSize){            head = 0;        }        elems--;        return tmp;    }    //是否已满    public boolean isFull(){        System.out.println("此时的元素个数为:"+elems);        System.out.println("tail="+tail);        return (tail == (maxSize-1));    }    //是否为空    public boolean isEmpty(){        return elems==0;    }    //返回有效的长度    public int getSize(){        return elems;    }}

测试：

public class TestMyQueue02 {    public static void main(String[] args) {        MyQueue02 myQueue02 = new MyQueue02(5);        myQueue02.insert(10);        myQueue02.insert(20);        myQueue02.insert(30);        myQueue02.insert(40);        myQueue02.insert(50);        System.out.println(myQueue02.isFull());        System.out.println(myQueue02.isEmpty());//        myQueue02.insert(100);        while (!myQueue02.isEmpty()){            System.out.println(myQueue02.remove());        }    }}

3、有序队列

public class MyQueue03 {    //数组    private int[] array;    //数组的最大长度    private int maxSize;    //有效数据的长度    private int elems;    public MyQueue03(int size){        this.maxSize = size;        array = new int[size];        elems = 0;    }    //插入数据    public void insert(int value){        int i;        for(i=0; i<elems; i++){            if(array[i] < value)                break;        }        for(int j=elems; j>i; j--){            array[j] = array[j-1];        }        array[i] = value;        elems++;    }    //删除数据    public int remove(){        return array[--elems];    }    //是否已满    public boolean isFull(){        return (elems == maxSize);    }    //是否为空    public boolean isEmpty(){        return elems==0;    }    //返回有效的长度    public int getSize(){        return elems;    }}

测试：

public class TestMyQueue03 {    public static void main(String[] args) {        MyQueue03 myQueue03 = new MyQueue03(5);        myQueue03.insert(10);        myQueue03.insert(20);        myQueue03.insert(30);        myQueue03.insert(40);        myQueue03.insert(50);        while (!myQueue03.isEmpty()){            System.out.print(myQueue03.remove()+" ");        }    }}