83. Remove Duplicates from Sorted List | Leetcode

 83. Remove Duplicates from Sorted List

Given the head of a sorted linked list, delete all duplicates such that each element appears only once. Return the linked list sorted as well.

 

Example 1:

Input: head = [1,1,2]
Output: [1,2]

Example 2:

Input: head = [1,1,2,3,3]
Output: [1,2,3]

 

Constraints:

• The number of nodes in the list is in the range [0, 300].
• -100 <= Node.val <= 100
• The list is guaranteed to be sorted in ascending order.

The solution to the above question is -

/**

 * Definition for singly-linked list.

 * struct ListNode {

 *     int val;

 *     ListNode *next;

 *     ListNode() : val(0), next(nullptr) {}

 *     ListNode(int x) : val(x), next(nullptr) {}

 *     ListNode(int x, ListNode *next) : val(x), next(next) {}

 * };

 */

class Solution {

public:

    ListNode* deleteDuplicates(ListNode* head) {

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

        ListNode* temp=head;

        int prev=temp->val;

        while(temp!=NULL){

                if( temp->next!=NULL && temp->next->val==prev){

                    temp->next=temp->next->next;

                }

                else{

                    temp=temp->next;

                    if(temp!=NULL)

                    prev=temp->val;

                    cout<<prev<<" ";

                }

            }

            

        return head;

    }

};