<p>You are given the <code>head</code> of a linked list.</p>

<p>Remove every node which has a node with a greater value anywhere to the right side of it.</p>

<p>Return <em>the </em><code>head</code><em> of the modified linked list.</em></p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2022/10/02/drawio.png" style="width: 631px; height: 51px;" />
<pre>
<strong>Input:</strong> head = [5,2,13,3,8]
<strong>Output:</strong> [13,8]
<strong>Explanation:</strong> The nodes that should be removed are 5, 2 and 3.
- Node 13 is to the right of node 5.
- Node 13 is to the right of node 2.
- Node 8 is to the right of node 3.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> head = [1,1,1,1]
<strong>Output:</strong> [1,1,1,1]
<strong>Explanation:</strong> Every node has value 1, so no nodes are removed.
</pre>

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

<ul>
	<li>The number of the nodes in the given list is in the range <code>[1, 10<sup>5</sup>]</code>.</li>
	<li><code>1 &lt;= Node.val &lt;= 10<sup>5</sup></code></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* removeNodes(ListNode* head) {
        ListNode* temp=head;
        int n=0;
        while(temp->next){
            n++;
            temp=temp->next;
        }
        n++;
        stack<int> st;;
        int nge[n];
        nge[n-1]=-1;
        st.push(temp->val);
        //reverse
        ListNode* currN=head,*prevN=NULL,*nextN;
        while(currN){
            nextN=currN->next;
            currN->next=prevN;
            prevN=currN;
            currN=nextN;
        }
        temp=prevN;
        temp=temp->next;
        int i=n-2;
        while(temp){
            while(st.size()>0 && st.top()<=temp->val) st.pop();
            if(st.size()==0) nge[i]=-1;
            else nge[i]=st.top();

            st.push(temp->val);
            temp=temp->next;
            i--;
        }
        //reverse
        currN=prevN,prevN=NULL;
        while(currN){
            nextN=currN->next;
            currN->next=prevN;
            prevN=currN;
            currN=nextN;
        }
      

        ListNode* c=new ListNode(10);
        ListNode* c2=c;
        c->next=head;
        temp=c;
        i=0;
        while(temp && temp->next){
            while(nge[i]!=-1){  
                temp=temp->next;
                i++;
            }
            
            temp=temp->next;
            c->next=temp;
            c=c->next;
            i++;
            
        }
        return c2->next;
    }
};
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