# 82. Remove Duplicates from Sorted List II
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
Example 1:
Input: 1->2->3->3->4->4->5
Output: 1->2->5
Example 2:
Input: 1->1->1->2->3
Output: 2->3
# Solution
Approach 1: Two pointers.
# Code (Python)
Approach 1:
# Code (C++)
Approach 1:
/**
* 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 == NULL)
return head;
ListNode dummyHead(0);
dummyHead.next = head;
ListNode *slow = &dummyHead;
ListNode *fast = head;
while (true)
{
if (!fast || fast->val != slow->next->val)
{
if (slow->next->next == fast)
slow = slow->next;
else
slow->next = fast;
}
if (!fast)
break;
fast = fast->next;
}
return dummyHead.next;
}
};