Delete nodes having greater value on right

Problem description:

Given a singly linked list, remove all the nodes which have a greater value on right side.
Input:
You have to complete the method which takes 1argument: the head of the linked list .You should not read any input from stdin/console.There are multiple test cases. For each test case, this method will be called individually.
Output:
Your function shouldreturn a pointer to the linked list in which all nodes which have a greater value on right side are removed.

Problem Link

/*

The structure of linked list is the following

struct Node
{
int data;
Node* next;
};

*/
Node *compute(Node *head)
{
// your code goes here
    int arr[150];
    int idx=0;
    Node *tmp=head,*prev,*nNode;
    Node *root;
    // if(head->next==NULL)
    // return head;
    while(tmp)
    {
        prev=tmp;
        arr[idx++]=prev->data;
        tmp=tmp->next;
    }
    int mx=arr[idx-1];
    root=new Node;
    root->data=arr[idx-1];
    if(idx>=2)
    for(int i=idx-2;i>=0;i--)
    {
        if(arr[i]>=mx)
        {
            mx=arr[i];
            nNode=new Node;
            nNode->data=mx;
            nNode->next=root;
            root=nNode;
        }
    }
    return root;

}