题解 | #删除有序链表中重复的元素-II#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    ListNode* deleteDuplicates(ListNode* head) {
        // write code here
        ListNode* new_head = new ListNode(1001);
        new_head->next = head;
        ListNode* pre = new_head;
        ListNode* cur = head;
        while (cur) {
            int val = cur->val;
            ListNode* next = cur->next;
            if (next && next->val == val) {
                while (cur && cur->val == val) {
                    cur = cur->next;
                }
                pre->next = cur;
            } else {
                pre = cur;
                cur = cur->next;
            }
        }
        return new_head->next;
    }
};