操作指针的题目
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* partition(ListNode* head, int x) {
if(head==NULL)
return head;
if(head->next==NULL)
return head;
ListNode *term = head;
ListNode *head2 = new ListNode(-1);
ListNode *head3 = head2;
int tag=0;
ListNode *pre = head;
while(term!=NULL)
{
if(term->val < x)
{
head2->next = term;
head2 = head2->next;
if(tag==0)
{
head = term->next;
pre = head;
}
else
{
pre->next = term->next;
}
}
else
{
tag=1;
pre = term;
}
term = term->next;
}
head2->next = head;
head = head3->next;
return head;
}
};