83. Remove Duplicates from Sorted List

/**
* 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) {
// IMPORTANT: Please reset any member data you declared, as
// the same Solution instance will be reused for each test case.
if(head == NULL || head->next == NULL)return head;
ListNode *index = head, *p = head->next, *pre = head;
while(p != NULL)
{
if(p->val != pre->val)
{
index = index->next;
index->val = p->val;
}
pre = p;
p = p->next;
}
p = index->next;
index->next = NULL;
while(p != NULL)
{//销毁多余的节点
ListNode *tmp = p;
p = p->next;
delete tmp;
}
return head;
}
};