<p>Given the <code>head</code> of a sorted linked list, <em>delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list</em>. Return <em>the linked list <strong>sorted</strong> as well</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/01/04/linkedlist1.jpg" style="width: 500px; height: 142px;" />
<pre>
<strong>Input:</strong> head = [1,2,3,3,4,4,5]
<strong>Output:</strong> [1,2,5]
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/01/04/linkedlist2.jpg" style="width: 500px; height: 205px;" />
<pre>
<strong>Input:</strong> head = [1,1,1,2,3]
<strong>Output:</strong> [2,3]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the list is in the range <code>[0, 300]</code>.</li>
	<li><code>-100 &lt;= Node.val &lt;= 100</code></li>
	<li>The list is guaranteed to be <strong>sorted</strong> in ascending order.</li>
</ul>

/**
 * 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) {
        ListNode* thead=new ListNode(-9999);
        thead->next=head;
        if(head==NULL){
            return head;
        }
        if(head->next==NULL){
            return head;
        }
        ListNode* prev=NULL;
        ListNode* curr=thead;
        ListNode* far=thead;

        int val=INT_MIN;

       
       ListNode* store=NULL;
       int count=0;

        while(curr!=NULL ){
            if(curr->val==val){
                count++;
               
                far=curr->next;
                prev->next=far;
                curr=far;
            }else{
                if(count>0){
                    store->next=curr;
                    prev=store;

                }
                count=0;
                
                val=curr->val;
                store=prev;

                prev=curr;
                curr=curr->next;
            }
            
            

        }
         if(count>0){
                    store->next=curr;
                    prev=store;

                }
        return thead->next;




        
    }
};
15500