Consider the following C program segment where CellNode represents a node in a binary tree:

struct CellNode 
{ 
     struct CellNOde *leftChild; 
     int element; 
     struct CellNode *rightChild; 
}; 

int GetValue(struct CellNode *ptr) 
{ 
     int value = 0; 
     if (ptr != NULL) 
     { 
       if ((ptr->leftChild == NULL) && 
        (ptr->rightChild == NULL)) 
       value = 1; 
       else 
         value = value + GetValue(ptr->leftChild) 
             + GetValue(ptr->rightChild); 
     } 
     return(value); 
} 

The value returned by GetValue() when a pointer to the root of a binary tree is passed as its argument is:

When searching for the key value 60 in a binary search tree, nodes containing the key values 10, 20, 40, 50, 70 80, 90 are traversed, not necessarily in the order given. How many different orders are possible in which these key values can occur on the search path from the root to the node containing the value 60?

The inorder and preorder traversal of a binary tree are d b e a f c g and a b d e c f g, respectively. The postorder traversal of the binary tree is:

An array X of n distinct integers is interpreted as a complete binary tree. The index of the first element of the array is 0. If the root node is at level 0, the level of element X[i], i ≠ 0, is