删除链表重复元素

class  {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        ListNode* h = NULL;
        ListNode* pre = NULL;
        ListNode* cur = head;
        ListNode* r = NULL;
        while (cur != NULL) {
            if (juge(pre, cur) && juge(cur, cur->next)) {
                if (h == NULL) {
                    h = new ListNode(cur->val);
                    r = h;
                } else {
                    r->next = new ListNode(cur->val);
                    r = r->next;
                }
            }
            pre = cur;
            cur = cur->next;
        }
        return h;
    }
    bool juge(ListNode* node1, ListNode* node2) {
        if (node1 == NULL || node2 == NULL || node1->val != node2->val) {
            return true;
        }
        return false;
    }
};