链表分割

ListNode* partition(ListNode* pHead, int x) {
        // write code here
        if (pHead == NULL || pHead->next == NULL) return pHead;
        
        ListNode* small=new ListNode(0);
        ListNode* big=new ListNode(0);
        ListNode *ps=small,*pb=big,*cur=pHead;
        
        while(cur)
        {
            if(cur->val<x)
            {
                ps->next=cur;
                ps=cur;
            }
            else
            {
                pb->next=cur;
                pb=cur;
            }
            cur=cur->next;
        }
        pb->next=nullptr;
        ps->next=big->next;
        return small->next;
    }