《Java数据结构与算法》笔记-CH5-链表-4用链表实现堆栈

//用链表实现堆栈
/**
 * 节点类
 */
class LinkS {
    private long data;
    public LinkS next;

    public LinkS(long d) {
        this.data = d;
    }

    public String toString() {
        return String.valueOf(data);
    }
}

/**
 * 链表类
 */
class LinkSList {
    private LinkS first;

    public LinkSList() {
        first = null;
    }

    public void insertFirst(LinkS node) {
        node.next = first;
        first = node;
    }

    public LinkS deleteFirst() {
        LinkS temp = first;
        first = first.next;
        return temp;
    }

    public boolean isEmpty() {
        return first == null;
    }

    public String toString() {
        if (isEmpty())
            return "[]";
        StringBuilder sb = new StringBuilder();
        sb.append("[");
        LinkS curr = first;
        while (curr != null) {
            sb.append(curr.toString()).append(",");
            curr = curr.next;
        }
        sb.deleteCharAt(sb.length() - 1);
        sb.append("]");
        return sb.toString();
    }
}

/**
 * 栈
 */
class LinkStack {
    private LinkSList linkList;

    public LinkStack() {
        this.linkList = new LinkSList();
    }

    public void push(LinkS l) {
        this.linkList.insertFirst(l);
    }

    public LinkS pop() {
        return this.linkList.deleteFirst();
    }

    public boolean isEmpty() {
        return this.linkList.isEmpty();
    }

    public String toString() {
        return this.linkList.toString();
    }

    public void display() {
        System.out.println(toString());
    }
}

public class LinkStackDemo {
    public static void main(String[] args) {
        LinkStack stack = new LinkStack();
        for (int i = 0; i < 5; i++) {
            LinkS l = new LinkS(i);
            stack.push(l);
            stack.display();
        }
        while (!stack.isEmpty()) {
            System.out.print("pop出" + stack.pop());
            System.out.print("现在栈为:");
            stack.display();
        }
    }
}