leetcode---剑指 Offer 24. 反转链表

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode* prev=nullptr;
        ListNode* curr=head;
        while(curr){
            ListNode* nextnode=curr->next;
            curr->next=prev;
            prev=curr;
            curr=nextnode;
        }
        return prev;
    }
};