2. (5 points) Suppose that there are n objects, 1,,n. Between any two different objects i and j, exactly one of the following is true: (1) i can be attached after j. (2) j can be attached after i. Given two objects i and j, you can figure out whether (1) or (2) is true in O(1) time. Design an algorithm that finds a permutation of the objects :{1,,n}{1,,n} such that object (i) can be attached to object (i1) for every 1