Remove Duplicates from Sorted List II

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

思路：

指针操作

代码：

    ListNode *deleteDuplicates(ListNode *head) {
        if(!head)
            return NULL;
        ListNode *result = NULL, *tail = NULL, *cur;
        cur = head;
        while(cur->next){
            if(cur->val == cur->next->val){
                int tmp = cur->val;
                while(cur){
                    if(cur->val != tmp)
                        break;
                    cur = cur->next;
                }
                if(!cur)
                    break;
            }
            else{
                if(!result){
                    result = cur;
                    tail = cur;
                }
                else{
                    tail->next = cur;
                    tail = tail->next;
                }
                cur = cur->next;
            }
        }
        if(tail)
            tail->next = cur;
        else
            result = cur;
        return result;
    }