Problem

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

Example

Input: 1->1->2
Output: 1->2

Input: 1->1->2->3->3
Output: 1->2->3

Code

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
static int var = [](){
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        if(head==NULL)
            return NULL;
        ListNode* newhead = new ListNode(head->val);
        ListNode* newtemp = newhead;
        ListNode* temp = head;
        while(temp!=NULL){
            if(newtemp->val!=temp->val){
                ListNode* newNode = new ListNode(temp->val);
                newtemp->next = newNode;
                newtemp = newtemp->next;
            }
            temp = temp->next;
        }
        return newhead;
    }
};

Result

83. Remove Duplicates from Sorted List.png