Problem 2: List of Books, (K Narayan Kumar / R Shreevatsa, CMI)
This is another problem about Indraneel's library. His library
has one long shelf. His books are numbered and he identifies the
books by their number. Each book has a distinct number.  He has
lost many books, since many of his friends borrow his books and
never bother to return them. He does not want to lose any more
books and has decided to keep a record of all books that he
lends to his friends. To make the task of borrowing a book a
little difficult, he has given the following instructions to his
friends: when they borrow a book, they must record in a register
its position from the left among the books currently on the
shelf.  Suppose there are 5 books in the library and they are
arranged as follows:  26  1  42  15  3  If someone walks in and
borrows the book 42, then he will record 3 in the register
because this book is the third from the left on the shelf. Now
the shelf looks like this:  26  1  15  3  If the next person
borrow the book 3, h