题解 | #删除有序链表中重复的元素-I#

/**
 * 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
     *
     * 就是简单的指针操作，设置前后两个指针，就可以啦
     * @param head ListNode类 
     * @return ListNode类
     */
    ListNode* deleteDuplicates(ListNode* head) {
        // write code here
        if (head == nullptr || head->next == nullptr)
          return head;

        auto pre = head;
        auto cur = head->next;
        while (cur != nullptr) {
          if (pre->val != cur->val) {
            pre = pre->next;
            cur = cur->next;
          } else {
            pre->next = cur->next;
            delete cur;
            cur = pre->next;
          }
        }

        return head;
    }
};