How to find if given binary tree is binary search tree?

Question

      40
      /\
     20 60
     /\  \
   10 30  80
      /   /\
     25  70 90
           \
           75

longest path 
25 30 20 40 60 80 70 75 
Answer
    25 ----> 75

Answer 1

Pseudo Code is something like this -

current = -infinite;

inorder(node, treeType)
{
   if node == null then return;

   inorder(node->left, treeType);
   if current >= node->data then treeType = "No BST"

   current = node-> data;
   inorder(node->right, treeType);
}

Call the function something like

inorder(head, "BST");

Comments

C++ program for the problem :-
http://www.csegeek.com/csegeek/view/tutorials/algorithms/trees/tree_part14.php