2. Consider a function for calculating the factorial of a number. (a) Please write the algorithm factorial (N) in a recursive structure. (b) List all the function calls in every step when executing factorial (5). (10%) 3. Draw the binary search tree whose elements are inserted in the following order: 517397108271312103112652171896(10%) 4. Examine the following algorithm (a) and (b) and apply it to the tree formed in problem (10%)