1. (10p) Show how to store a set of distinct numbers and support the following operations (using augmenting data structures): insert(x): adds x to the set (assume that so is not in the set when this operation is called). delete(x): removes x from the set (assume that x is already in the set when this operation is called). extract(x,y); returns one element of the set that is closest to the average of all numbers - in the set such that x