Remove Duplicates from Sorted List Recursively.cpp

/**
 * 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;
        while(temp->next!=NULL){
            if(temp->val==temp->next->val){
                ListNode *del = temp->next;
                temp->next = del->next;
                delete(del);
                
            }else{
                temp=temp->next;
            }
        }
      return head;  
    }
};