题目:
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5
, return 1->2->5
.
Given 1->1->1->2->3
, return 2->3
.
分类:Linked List
代码:维护两个指针ptr,pre
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* deleteDuplicates(ListNode* head) {
if(!head)
return head;
if(head && !head->next)
return head;
ListNode *newHead = new ListNode(head->val - );
newHead->next = head;
ListNode *pre = newHead;
ListNode *ptr = newHead;
while(head)
{
if(pre->val != head->val && (!head->next || head->val != head->next->val))
{
ptr->next = head;
ptr = ptr->next;
}
pre = head;
head = head->next;
}
ptr->next = NULL; return newHead->next;
}
};