The main focus of this assignment is recursive call and placing strings in link list nodes. the material from ch1 ~ 9 of the textbook can help you tremendously. you can get a lot of good information about implementing this assignment from chapter 9. you need to write a permute class that will take first and second strings to rearrange letters in first, followed by second. for example, if the first is "cat" string and second is "man" string, then the program would print the strings tacman, atcman, ctaman, tcaman, actman, and catman. the first and second strings can be any length of string or a null.