suppose we have an unsorted array a of n elements and we want to know if the array contains any duplicate elements. (a) outline an efficient method for solving this problem. (b) what is the asymptotic order of running time of your method in the worst case? (c) suppose we know the n elements are integers from the range 1,...,2n, so other operations besides comparing keys may be done. give an algorithm for the same problem that is specified to use this information. tell the asymptotic order of the worst-case running time for this solution. it should be of lower order than your solution for part (a).