【Leetcode】删除排序链表中的重复元素

 1 /**
 2  * Definition for singly-linked list.
 3  * struct ListNode {
 4  *     int val;
 5  *     ListNode *next;
 6  *     ListNode(int x) : val(x), next(NULL) {}
 7  * };
 8  */
 9 class Solution {
10 public:
11     ListNode* deleteDuplicates(ListNode* head) {
12         if(head == NULL)    return head;
13         ListNode* pre = head;
14         ListNode* cur = head;
15         ListNode* nxt = head;
16 
17         while(cur){
18             //如果相同
19             if(cur->next!=NULL && cur->next->val == cur->val){
20                 nxt = cur->next;
21                 //一直找到不相同的值
22                 while(nxt->next!=NULL && nxt->next->val == cur->val){
23                     nxt = nxt->next;
24                 }
25                 //如果是头节点，这里注意保留一个元素
26                 if(cur == head) head = nxt; 
27                 //不是头节点
28                 else    pre->next = nxt;
29                 //更新节点
30                 cur = nxt;
31             }
32             else{   //不相同直接向后走
33                 pre = cur;
34                 cur = cur->next;
35             }
36         }
37 
38 
39         return head;
40     }
41 };