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 || !head->next){
            return head;
        }
        auto *pre = head;
        ListNode *next;
        while(pre!=nullptr){
            next = pre->next;
            while(next != nullptr &&  pre->val == next->val){
                next = next->next;
            }
            pre->next = next;
            pre = pre->next;
        }
        return head;
    }
};