Add all sum of nodes which are greater than current node in given BST

18.cpp

// Calculate whole sum 
//1.)Traverse the BST and calculate the total sum of all the nodes
//2.) Again start "Inorder Traversing" and replace the first node with the calculated sum in step 1
//3.) Subtract that first node from the sum and move forward to the second node.
//4.) Again keep on replacing and subtracting till you finish the inorder traversal
//Complexity O(n+n)

void sum_modify(t, tsum){
  inorder(t->left, tsum);
  t->data = tsum;
  tsum = tsum - t->data;
  inorder(t->right, tsum);
}