listNode 节点类

1 成员变量：val next
2 构造函数

package byteDance_test;

public class listNode {
    char val;
    listNode next;
    listNode(char val){
        this.val = val;
    }
}

linkList 链表类

1 成员变量：head、tail节点，size
2 构造函数
3 添加元素函数
4 简单的显示函数
5 反转函数

package byteDance_test;

public class linkList {
    listNode head;
    listNode tail;
    int size;
    linkList(){
        head = null;
        tail = null;
        size = 0;
    }

    public void add (listNode node){
        if(head == null){
            head = node;
            tail = node;
            size++;
        }
        else {
            tail.next = node;
            tail = node;
            size++;
        }
    }

    public void display(){
        listNode cur = head;
        while (cur!=null){
            System.out.println(cur.val+"->");
            cur=cur.next;
        }
    }

    public void reverseLink(){
        listNode cur = head;
        listNode prev = null;
        while (cur!=null){
            listNode Next = cur.next;
            cur.next = prev;
            prev = cur;
            cur = Next;
        }

        head = prev;
    }
}

反转函数

变量使用 listNode：cur、next、prev
1 prev 初始化为null，作为最终的尾节点
2 cur 从head 开始遍历 ，将其next 指向prev， 然后依次向后移动prev和cur

public void reverseLink(){
    listNode cur = head;
    listNode prev = null;
    while (cur!=null){
        listNode Next = cur.next;
        cur.next = prev;
        prev = cur;
        cur = Next;
    }

    head = prev;
}

主函数验证

package byteDance_test;

public class main {
    public static void main(String[] args) {
        listNode node_1 = new listNode('a');
        listNode node_2 = new listNode('b');
        listNode node_3 = new listNode('c');
        listNode node_4 = new listNode('d');
        listNode node_5 = new listNode('e');

        linkList list = new linkList();

        list.add(node_1);
        list.add(node_2);
        list.add(node_3);
        list.add(node_4);
        list.add(node_5);
        
        list.display();
        System.out.println("----------");
        list.reverseLink();
        list.display();
    }
}

验证结果