ForceBook

package com.company;

import java.util.*;

public class Main {

    static String newSide = "";

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        HashMap<String, List<String>> map = new HashMap<>();


        String command = sc.nextLine();


        while (!"Lumpawaroo".equals(command)) {


            ArrayList<String> list = new ArrayList<>();

            if (command.contains("|")) {

                String[] commandParts = command.split("\\s+");

                if (!map.containsKey(commandParts[0])) {
                    list.add(commandParts[2]);
                    map.put(commandParts[0], list);
                } else {
                    map.get(commandParts[0]).add(commandParts[2]);
                    map.put(commandParts[0], map.get(commandParts[0])); // try without this one
                }
            }
            if (command.contains("->")) {

                String[] commandParts = command.split(" -> ");

                map.entrySet().stream().filter(e -> !e.getKey().equals(commandParts[1]))
                        .forEach(stringListEntry -> newSide = stringListEntry.getKey());

                if (map.get(commandParts[1]).contains(commandParts[0])) {
                    map.get(commandParts[1]).remove(commandParts[0]);

                    map.get(newSide).add(commandParts[0]);
                    System.out.println(String.format("%s joins the %s side!", commandParts[0], newSide));

                } else {
                    if (map.get(newSide).contains(commandParts[0])) {
                        map.get(newSide).remove(commandParts[0]);

                        map.get(commandParts[1]).add(commandParts[0]);
                    } else {
                        map.get(commandParts[1]).add(commandParts[0]);
                        map.put(commandParts[1], map.get(commandParts[1]));
                    }
                    System.out.println(String.format("%s joins the %s side!", commandParts[0], commandParts[1]));

                }
            }
            command = sc.nextLine();
        }

        map.entrySet().stream().filter(e -> e.getValue().size() > 0)
                .sorted((n1, n2) -> Integer.compare(n2.getValue().size(), n1.getValue().size()))
                .forEach(stringListEntry -> {
                    System.out.println(String.format("Side: %s, Members: %d",
                            stringListEntry.getKey(), stringListEntry.getValue().size()));
                    Collections.sort(stringListEntry.getValue());
                    for (String s :
                            stringListEntry.getValue()) {
                        System.out.println(String.format("! %s",s));
                    }

                });


    }
}