Java数据结构与算法之顺序表和链表实现栈和队列

我看了几个网上的实现，不太满意，所以在重新复习的时候，顺便把它们再实现一遍

• 链栈

/**
 * @author Obj9527
 *
 */

public class LinkedStack{
    LNode<Object> head = null;//头节点

    /*
     * 内部类用来定义单链表节点
     */
    private class LNode<T>{
        T data;
        public LNode<T> next;

        public LNode(T data) {
            this.data = data;
        }

        @Override
        public String toString() {
            return data.toString();
        }
    }

    public LinkedStack(Object data) {       
        head = new LNode<Object>(data);
    }

    /*
     * 用头插法入栈实现LIFO，链栈采用的是非连续内存区域，
     * 不需要考虑栈满，除非物理内存爆了
     */
    public void push(Object data) {
        LNode<Object> node = new LNode<Object>(data);
        node.next = head.next;
        head.next = node;
    }

    /*
     * Java不能手动指定销毁对象，所以这里不用管freeNode，
     * 让Java垃圾回收器自己处理，出栈需要考虑栈空，所以需要
     * 进行空栈判断
     */
    public Object pop() {
        if (head.next == null) {
            throw new RuntimeException("The Stack is empty");
        }

        LNode<Object> freeNode = head.next;
        head.next = freeNode.next;
        return freeNode.data;
    }
}

• 顺序栈

/**
 * @author Obj9527
 *
 */

public class ArrayStack{
    private int data[] = null;//数据域
    private int top = -1;//指针

    public ArrayStack(int maxSize) {
        data = new int[maxSize];
    }

    /*
     * 入栈
     */
    public void push(int num) {
        if (top == data.length-1) {
            throw new RuntimeException("stack is full");
        }

        data[(++top)] = num;
    }

    /*
     * 出栈
     */
    public int pop() {
        if (isEmpty()) {
            throw new RuntimeException("stack is empty");
        }

        return data[(top--)];
    }

    /*
     * 判断栈空
     */
    public boolean isEmpty() {
        if (top == -1) {
            return true;
        }
        return false;
    }
}

• 顺序队

/**
 * @author Obj9527
 *
 */

public class ArrayQuene {
    int data[] = null;//数据域
    int front = 0;//头指针
    int rear = 0;//尾指针

    /*
     * 创建时赋予队列大小
     */
    public ArrayQuene(int maxSize) {
        data = new int[maxSize];
    }

    /*
     * 入队
     */
    public void enQuene(int value) {
        if ((rear+1) % this.data.length == front) {
            throw new RuntimeException("The Quene is full");
        }

        rear = (rear+1) % this.data.length;
        data[rear] = value;
    }

    /*
     * 出队
     */
    public int deQuene() {
        if (front == rear) {
            throw new RuntimeException("The Quene is empty");
        }

        front = (front + 1) % this.data.length;
        return data[front];
    }
}

• 链队

/**
 * @author Obj9527
 *
 */

public class LinkedQuene {
    private QNode<Object> front = new QNode<Object>("head");//头指针
    private QNode<Object> rear = front;//尾指针

    /*
     * 队节点
     */
    class QNode<T>{
        T data;
        QNode<T> next;

        public QNode(T value) {
            this.data = value;
        }

        @Override
        public String toString() {
            return this.data.toString();
        }
    }

    /*
     * 入队
     */
    public void enQuene(Object value) {
        QNode<Object> qNode = new QNode<Object>(value);
        rear.next = qNode;
        rear = qNode;
    }

    /*
     * 出队
     */
    public Object deQuene() {
        if (front == rear) {
            throw new RuntimeException("The Quene is empty!");
        }

        front = front.next;
        return front.data;
    }
}