题解 | #删除有序链表中重复的元素-I#

双指针，flag标记唯一数，cur标记当前位

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        if(!head) return head;
        // write code here
        ListNode* cur = head;
        ListNode* flag = head;
        while(cur){
            if(flag == cur){//相等时，找下一个
                cur = cur->next;
            }else if(flag != cur && flag->val != cur->val){//不相等时，移动
                flag = cur;
            }else if(flag != cur && flag->val == cur->val){//删除节点
                flag->next = cur->next;
                free(cur);
                cur = flag->next;
            }
        }
        return head;
    }
};