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im having a hard time understanding Maps and i was asked to make a SortedMap with a different key and value out of another map using a comparator and a supplier. Its said to us that the "teams" key is the name of a team and the value is the information of the team, and the new sorted map has as a key the points that a team has and as a value the colection of team names with that points, the colection is given by the supplier. i dont get how i will make that happen. i thought of verifing if in "teams" there is a key with on of the suppliers name by iterating this one and if there was i would save that name in an List. but after that i dont know how i would build the SortedMap. Any suggestions?

Edited: This was what i did.

public static <C extends Collection<String>> SortedMap<Integer, C> toTable(Map<String, Team> teams, Comparator<Integer> cmp, Supplier<C> supplier) {
  SortedMap<Integer, C> sm = new TreeMap<Integer, C>(cmp);
  List<C> aux= new ArrayList<C>();
  C newTeam = null;
  int totalNames = supplier.get().size();
  while(totalNames>0) {
    if(teams.containsKey(supplier.get().iterator().next()))
        aux.add(supplier.get());
        totalNames--;
  }

  int size = aux.size();
  while (size>0){
    sm.put(1/*how to get a new key*/,aux.iterator().next());
    size--;
  }

return sm;
}
João Maia
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    Your question explanation is not good enough thus the problem is unclear. First when you ask a question do not write it in a style as if you are talking to a friend instead use a formal style and describe the key points and problems you encountered while IMPLEMENTING the solution. Second you have to IMPLEMENT the solution and the get stuck and search for solutions if no success finally come here and ask the question. – Aziz Gasimov Dec 28 '21 at 05:56
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    Could you please share the code sample? – Noman ali abbasi Dec 28 '21 at 06:37
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    Post code as text rather than image. – Basil Bourque Dec 28 '21 at 07:16

1 Answers1

0

Turns out my interpretation of the problem was off and after half a day trying to solve it understood that my use of the supplier was completely off. What i should have done was cycle through the Map teams.values() and for each Team verify if the number of points already existed as a key on the Map sm. If it existed, i should get the values associated and add the new team name with methods get on sm. If it didn't, using the supplier i should obtain a new list (using the method get on supplier) and add to this list the new team name. finally i should place in sm a new entry with the number of points and the new list (using method put)

Solution:

public static <C extends Collection<String>> SortedMap<Integer, C> toTable(Map<String, Team> teams, Comparator<Integer> cmp,
                                                                               Supplier<C> supplier) {
        SortedMap<Integer, C> sm = new TreeMap<Integer, C>(cmp);
        C newTeam = null;
        for (Team t: teams.values()){
            if(sm.containsKey(t.getPoints())) {
                sm.get(t.getPoints());
                newTeam.add(t.getName());
            }
            else{
                newTeam = supplier.get();
                newTeam.add(t.getName());
                sm.put(t.getPoints(),newTeam);
            }
        }
        return sm;
    }
João Maia
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