(20 pts) Consider the railroad switching networks given in Figure 1. The railroad switching network using a stack is referred to as Net-stack as Figure 1(a) shows. Railroad cars 0,1, ,n-1 are at right. Each car is brought into the stack and moved any time. For example, if n 3, we can move in 0, move in 1, move in 2, and then we take the cars out, producing the new order 2, 1, 0. If we replace the stack in the railroad switching network by a queue as shown in Figure 1(b), the switching network becomes a Net-queue. 2. Queue (a)using a stack (busing a queue Figure 1: Railroad switching networks (a) Net-stack and (b) Net-queue (a) For n = 3 and n = 4, what are the possible permutations of the cars that can be obtained using Net-stack? Are any permutations not possible? (b) For n 3 (say, 0, 1, 2), what are the permutations we can obtain using Net-queue