[leetcode] Remove Duplicates from Sorted List II

Remove Duplicates from Sorted List IIApr
22 '12

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

.

与Remove Duplicates from Sorted List的区别在于需要将所有有重复的节点删掉，考虑可以用一个set保存重复的值，注意指针不要出界。

class Solution {
public:
ListNode *deleteDuplicates(ListNode *head) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
set<int> s;
ListNode *cur=head;
if(!head) return cur;
while(cur)
{
if(cur->next && cur->next->val==cur->val)
{
ListNode *temp=cur->next;
cur->next=cur->next->next;
s.insert(cur->val);
delete temp;
}
else cur=cur->next;
}
ListNode *newhead=new ListNode(0);
cur=newhead;
cur->next=head;
while(!s.empty())
{
if(cur->next->val==*(s.begin()))
{
s.erase(s.begin());
cur->next=cur->next->next;
}
else cur=cur->next;
}
head=newhead->next;
delete newhead;
return head;
}
};