82. Remove Duplicates from Sorted List II

对于这种链表题已经很熟练了，一次AC

/** * Definition for singly-linked list. * struct ListNode { *     int val; *     ListNode *next; *     ListNode(int x) : val(x), next(NULL) {} * }; */class Solution {public:    ListNode* deleteDuplicates(ListNode* head) {        if(head==NULL)            return NULL;        ListNode* prenow=NULL;        ListNode* now=head;        ListNode* next=head->next;        while(next!=NULL)        {            if(now->val==next->val)            {                while(next!=NULL&&now->val==next->val)                    next=next->next;                if(prenow==NULL)                    head=next;                else                    prenow->next=next;                now=next;                if(next!=NULL)                    next=next->next;            }            else            {                prenow=now;                now=next;                next=next->next;            }        }        return head;    }};