public static long roadsAndLibraries(int n, int c_lib, int c_road, List<List<Integer>> cities) {
        if(cities.isEmpty() || c_lib <= c_road) return 1L * n * c_lib;
        
        TreeMap<Integer, Stack<Integer>> cityMap = new TreeMap<>();
        for(List<Integer> connection: cities){
            int c1 = connection.get(0), c2 = connection.get(1);
            cityMap.computeIfAbsent(c1, k -> new Stack<>()).add(c2);
            cityMap.computeIfAbsent(c2, k -> new Stack<>()).add(c1);
        }
        
        long libs = n - cityMap.size(), roads = 0L;
        
        while(!cityMap.isEmpty()){
            // Start new cycle
            libs++;
            Stack<Integer> stack = cityMap.pollFirstEntry().getValue();
            while(!stack.isEmpty()) {
                // DFS for connected cities
                int c = stack.pop();
                if(cityMap.containsKey(c)){
                    roads++;
                    stack.addAll(cityMap.remove(c));
                }
            }
        }
        
        return libs * c_lib + roads * c_road;
    }