public static long roadsAndLibraries(int n, int c_lib, int c_road, List<List<Integer>> cities) {
        if(c_lib <= c_road || cities == null || cities.size() == 0)
            return c_lib * n;
        
        List<List<Integer>> adj = new ArrayList<>(n);
        for(int i = 0; i < n; i++){
            adj.add(new ArrayList<>());
        }
        for(int i = 0; i < cities.size(); i++){
            int u = cities.get(i).get(0) - 1;
            int v = cities.get(i).get(1) - 1;
            adj.get(u).add(v);
            adj.get(v).add(u);
        }
        boolean[] visited = new boolean[n];
        long clusters = 0;
        for(int i = 0; i < n; i++){
            if(visited[i]) continue;
            clusters++;
            Queue<Integer> subGraph = new LinkedList<>();
            subGraph.offer(i);
            while(!subGraph.isEmpty()){
                int curr = subGraph.poll();
                if(visited[curr]) continue;
                visited[curr] = true;
                //subGraph.addAll(adj.get(curr));
                for(Integer next : adj.get(curr)) {
                    if(!visited[next]) subGraph.add(next);
                }
            }
        }

        return (long)(clusters * c_lib) + (long)(n - clusters) * c_road;
    }