# 83. Remove Duplicates from Sorted List
Given a sorted linked list, delete all duplicates such that each element appear only once.
Example 1:
Input: 1->1->2
Output: 1->2
Example 2:
Input: 1->1->2->3->3
Output: 1->2->3
# Solution
Approach 1: Straight-Forward Approach.
# 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 NULL;
ListNode *slow = head;
ListNode *fast = head->next;
while (fast != NULL)
{
if (fast->val != slow->val)
{
slow->next = fast;
slow = fast;
}
fast = fast->next;
}
slow->next = NULL;
return head;
}
};
class Solution {
public:
ListNode* deleteDuplicates(ListNode* head) {
ListNode *p = head;
while (p && p->next)
{
if (p->val == p->next->val)
p->next = p->next->next;
else
p = p->next;
}
return head;
}
};