Function of the redo and undo

The three logical operators used to write compound conditions are "and," "or," and "not." a: true b: false

Write a method named addall that could be placed inside the hashintset class. this method accepts another hashintset as a parameter and adds all elements from that set into the current set, if they are not already present. for example, if a set s1 contains [1, 2, 3] and another set s2 contains [1, 7, 3, 9], the call of s1.addall(s2); would change s1 to store [1, 2, 3, 7, 9] in some order. you are allowed to call methods on your set and/or the other set. do not modify the set passed in. this method should run in o(n) time where n is the number of elements in the parameter set passed in.

One of your customers wants you to build a personal server that he can use in his home. one of his concerns is making sure he has at least one backup of their data stored on the server in the event that a disk fails. you have decided to back up his data using raid. since this server is for personal use only, the customer wants to keep costs down. therefore, he would like to keep the number of drives to a minimum. which of the following raid systems would best meet the customer's specifications? a. raid 0 b. raid 1 c. raid 5 d. raid 10