Alternating Channel Signal Routes

A city control room has n signal stations numbered from 0 to n - 1. Two separate one-way cable systems connect the stations: copper links and fiber links. A signal starts from station 0. For safety reasons, a route is valid only if consecutive moves use different cable systems. The first move may use either copper or fiber. A station may be reached with different last-used cable types, and those situations are considered different route states. For every station, determine the fewest links needed to reach it from station 0 while obeying the alternating-channel rule. If no valid alternating route reaches a station, mark it as -1. Input Format: You are given n, an array copperLinks, and an array fiberLinks. Each link is represented as [from, to]. Output Format: Return an array answer where answer[i] is the minimum number of valid moves needed to reach station i, or -1 if station i is unreachable.