java - 从链表中删除节点

Question

class StackNode{
    int data;
    StackNode next;

    public StackNode(int data, StackNode next){
        this.data = data;
        this.next = next;
    }
}

public class StackWithLinkedList {

    StackNode root = null;

    public void push(int data){
        if(root == null)
            root = new StackNode(data, null);
        else {
            StackNode temp = root;
            while(temp.next != null)
                temp = temp.next;

            temp.next = new StackNode(data, null);
        }
    }

    public int pop() throws Exception{
        if(root == null)
            throw new Exception("No Elements in Stack");
        else {
            StackNode temp = root;
            while(temp.next != null)
                temp = temp.next;
            int data = temp.data;
            temp = null;
            return data;
        }
    }


    public void print(){
        StackNode temp = root;
        while(temp!= null){
            System.out.print(temp.data +" ");
            temp = temp.next;
        }
        System.out.print("\n");
    }

    public static void main(String[] args) {
        StackWithLinkedList stack = new StackWithLinkedList();
        for(int i = 1; i<=15; i++){
            Random randomGen = new Random();
            stack.push(randomGen.nextInt(i));
        }
        stack.print();
        System.out.print("\n");
        try {
            System.out.println("Deleted: "+stack.pop());
            System.out.println("Deleted: "+stack.pop());
        } catch (Exception e) {
            e.printStackTrace();
        }
        stack.print();
    }
}

我正在尝试使用 Linkedlist 实现 Stack。在 pop 函数中，我遍历到最后一个节点并将其设为空。当我打印列表时。它保持不变。将 root 分配给 temp 并使用它遍历会导致任何问题吗？

Answer 1

您可以通过简化实现来避免这一切。它只是一个堆栈，所以它是 LIFO。您需要做的就是将最后一个元素push 加入root。当 pop-ing 返回 root 中的 data 并将 root 设置为下一行。

对于 push 和 pop 操作。

类似于:

public void push(int data) {
    root = new StackNode(data, root);
}

public int pop() throws Exception {
    if (root == null)
        throw new Exception("No Elements in Stack");
    else {
        int data = root.data;
        root = root.next;
        return data;
    }
}