快指针和慢指针
ListNode *slow = head;
ListNode *fast = head;
while(fast)
{
slow = slow->next;
fast = fast->next ? fast->next->next: fast->next;
}
快指针指向末尾,退出循环
链表翻转(递归)
ListNode* rev(ListNode* h)
{
if(h==NULL or h->next==NULL)
return h;
ListNode *p=rev(h->next);
h->next->next=h;
h->next=NULL;
return p;
}
还有一种借助临时变量
链表翻转(借助临时变量)
ListNode* reverseList(ListNode* head)
{
ListNode *p1,*p2;
p1 = head;
p2 = NULL;
if(p1 == NULL) return head;
while(p1 != NULL)
{
ListNode *temp = p1->next;
p1->next = p2;
p2 = p1;
p1 = temp;
}
return p2;
}