Let S be the set consisting of all 10 digits and all upper and lowercase letters Let U be the set of all ordered strings consisting of exactly four elements from S Construct an injective hash function h U N with the smallest possible value of maxUh u Modify your hash function to give a simply uniform map h to the set 0 30 In other words if U is a probability space with P u P u for all u u in U then the random variable h U 0 30 should have a uniform distribution