题解 | #牛群排列去重#

/**
 * 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
        if (head == nullptr || head->next == nullptr) {
            return head;
        }
        ListNode* h = head;
        ListNode* pre = head, *cur = head->next;
        while (cur != nullptr) {
            if (cur->val == pre->val) {
                ListNode* temp = cur;
                cur = cur->next;
                pre->next = cur;
                delete temp;
            } else {
                pre = pre->next;
                cur = cur->next;
            }
        }
        return h;
    }
};