1. You are given two STL lists X and P where P is already in sorted order. Write a valid C++ function printPositions(X, P) that prints the elements in X specied by P. For example, if P = 0, 2, 5, 6, the elements in positions 0 (head of the list), 2, 5, and 6 in X are printed. You may use only the public STL container operations. Also specify the running time of your algorithm using Big-Oh notation. Hint: You may wish to use iterators while keeping track of the position of items being iterated through.