[LeetCode] Remove Duplicates from Sorted Linked List 从排序链表中去掉重复值

Given a sorted linked list, delete all duplicates such that each element appear only once. For example, Given

1->1->2

,
return

1->2

. Given

1->1->2->3->3

,
return

1->2->3

.

相关问题1：压缩字符串

相关问题2-1：Remove Duplicates from Sorted Linked List
I

相关问题2-2：[LeetCode] Remove Duplicates from Sorted List II

相关问题3：[LeetCode] Remove Duplicates From Sorted
Array I
相关问题 4：[LeetCode] Remove Duplicates From Sorted
Array II
思路和相关问题3和相关问题4 完全一样：fast-val是和A[j-1] 相当，fast->next->val和A[j]相当。注意，新链表和原来的链表可能有不一样的头指针。

ListNode *deleteDuplicates(ListNode *head) {

ListNode* newHead=NULL;

ListNode* slow = NULL;
ListNode* fast = head;

if(head==NULL) return NULL;
if(head->next==NULL) return head;

while(fast->next)
{
if(fast->val!=fast->next->val) // A[j-1]!=A[j]
{
if(slow==NULL)
newHead = fast;
else
slow->next = fast;

slow = fast;
}

fast = fast->next;
}

if(slow==NULL)
newHead = fast;
else
slow->next = fast;

slow = fast;
fast = fast->next;

return newHead;
}