题解 | #反转链表#

struct ListNode* ReverseList(struct ListNode* head ) {
    struct ListNode *n1=NULL,*n2=head,*n3=head->next;
    if(head)
    {
        while(n2)
        {
            n2->next=n1;
            n1=n2;
            n2=n3;
            if(n3)
            n3=n2->next;
        }
    }
    return n1;
}