题解 | #删除有序链表中重复的元素-I#

双指针

用双指针遍历链表，有重复的直接进行删除操作，注意初始化

C++代码：

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        if (!head || !head->next) {return head;}
        ListNode *pre = head, *p = head->next;
        while (p) {
            if (pre->val == p->val) {
                pre->next = p->next;
            } else {
                pre = p;
            }
            p = p->next;
        }
        return head;
    }
};