每天刷一道牛客题霸-第1天-反转链表

1. Go语言版本

   package main
   import . "nc_tools"
   func ReverseList( pHead *ListNode ) *ListNode {
    if pHead == nil {
        return nil
    }
    VirtualRoot := &ListNode{Val: 0}
    VirtualRoot.Next = pHead
    start := VirtualRoot.Next
    next  := start.Next
    for next != nil {
        start.Next = next.Next
        next.Next = VirtualRoot.Next
        VirtualRoot.Next = next
        next = start.Next
    }
   
    return VirtualRoot.Next
    // write code here
   }

2. Java版本

   import java.util.*;
   public class Solution {
    public ListNode ReverseList(ListNode head) {
        if(head == null){
            return null;
        }
        // 设置虚拟节点
        ListNode virtualRoot = new ListNode(0);
   
        virtualRoot.next = head;
        // start节点保持不变,一直指向head
        ListNode start = head;
        ListNode next = head.next;
        while(start.next != null){
            start.next =  next.next;
            next.next = virtualRoot.next;
            virtualRoot.next = next;
            next = start.next;
        }
        return virtualRoot.next;
    }
   }

题目链接

https://www.nowcoder.com/practice/75e878df47f24fdc9dc3e400ec6058ca?tpId=190&&tqId=35203&rp=1&ru=/activity/oj&qru=/ta/job-code-high-rd/question-ranking