2. (hard) Each baby has brown hair or purple hair or black hair. Design a one-pass and in-place and and linear time algorithm to sort the babies according to their hair color: brown hair babies followed by purple hair babies and then followed by black hair babies. Can you use only three pointers? If you need more than three pointers, how many do you need? (Remember that each pointer is one-pass.) I need almost working psuedo-code.