没啥重点，直接贴

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
      if (head == nullptr || head->next == nullptr) {
        return head;
      }
      
      ListNode *cur = head, *nex = head->next;
      
      while (nex) {
        if (nex->val == cur->val) {
          cur->next = nex->next;
          delete(nex);
          nex = cur->next;
        } else {
          cur = nex;
          nex = nex->next;
        }
      }
      
      return head;
    }
};