Let A = {a_1, a_2, ..., a_n}, B = {b_1, b_2, ..., b_n}, and C = {c_1, c_2, ..., c_n} be three sets of numbers. Design a presorting-based algorithm for finding their intersection, i.e. the set containing all the numbers belonging to A, B, and C. The algorithm should be in the nlogn efficiency class Rubrics: brute-force: 1, using sorting: 3, specifying indices for the intersection: 4; reduce 1 point for not complying with pseudocode rules