Let S be a stack of size n >= 1. Starting with the empty stack, suppose we push the first n natural numbers in sequence, and then perform n pop operations. Assume that Push and Pop operations take X seconds each, and Y seconds elapse between the end of one such stack operation and the start of the next operation. For m >= 1, define the stack-life of m as the time elapsed from the end of Push(m) to the start of the pop operation that removes m from S. The average stack-life of an element of this stack is

Consider the function f defined below.

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

int f(struct item *p) { 
      return ((p == NULL) || (p ->next == NULL) || 
        ((p->data <= p -> next -> data) && 
        f(p-> next))); 
}

For a given linked list p, the function f returns 1 if and only if

Consider the following graph among the following sequences
I. a b e g h f
II. a b f e h g
III. a b f h g e
IV. a f g h b e
What are depth first traversals of the above graph?

Suppose the numbers 7, 5, 1, 8, 3, 6, 0, 9, 4, 2 are inserted in that order into an initially empty binary search tree. The binary search tree uses the usual ordering on natural numbers. What is the in-order traversal sequence of the resultant tree?