如何根据数组列表中每个对象的属性将自定义对象的数组列表分成 x 组？

Question

I have been trying to figure this one out, and I'm still scratching my head. I need to divide an arraylist of objects (people in this case) into equal groups of 6, from a total of 12-25 people. They need to be divided into teams of 6 with both halves sorted by the best of both the AttackStat and the DefenseStat of each person object. I have already written algorithms to sort the arraylist based on the best of each stat, but I'm not sure how to implement a way to display groups of six with no repeating names.

I am given the instruction:

Your program will need to be able to divide a roster into the maximum possible number of teams. For example, a roster with 18 players on it would be divided up into three different scrimmage teams with 6 players each. A roster file will always contain a list of between 12 and 25 players, and a scrimmage team always has 6 players.

The coach would like the teams to be reasonably well balanced. To do this, your program should make up half of each scrimmage team by distributing the best attackers to each of the different teams. For example, a roster with 12 players on it would be divided up into 2 scrimmage teams, and three of the top 6 attackers would be assigned to each of the two scrimmage teams. After the top attackers have been assigned to make up half of each scrimmage team, then the top blockers (from the remaining unassigned players) would similarly be assigned (three to each scrimmage team in this example) to make up the other half of each team.

Here's some of what I have right now in my Roster class:

    void sortbyAttack() {
    peopleArrayList.sort(Comparator.comparing(Person::getAttackStat).reversed());
}

void sortbyDefense() {
    peopleArrayList.sort(Comparator.comparing(Person::getDefenseStat).reversed());
}

void makeTeams() {
    ArrayList<String> team1 = new ArrayList<>();
    ArrayList<String> team2 = new ArrayList<>();
    ArrayList<String> team3 = new ArrayList<>();
    ArrayList<String> team4 = new ArrayList<>();

    sortbyAttack();
    for (int i = 0; i < 6; i++) {
        team1.add(peopleArrayList.get(i).toString());
    }
    for (int i = 6; i < 12; i++) {
        team2.add(peopleArrayList.get(i).toString());
    }
    for (int i = 0; i < 3; i++) {
        team3.add(team1.get(i).toString());
        team3.add(team2.get(i).toString());
    }
    for (int i = 3; i < 6; i++) {
        team4.add(team1.get(i).toString());
        team4.add(team2.get(i).toString());
    }
    System.out.println(team1 + "\n" + team2);
    System.out.println(team3 + "\n" + team4);
  }
}

I have tried to figure this out, I looked all over this site and googled it about a hundred times, but I can't seem to find a proper way to implement the sorting and dividing and distributing my custom objects by local values into the max amount of groups of six, without any repeating people on the same scrimmage team.

Answer 1

First of all the condition on your loops forces the team to be one specific length, in this case 36 because I suppose you don't want duplicated players on teams. I'm pretty sure your professor wants a solution able to work for n players.

This said, I think you got to work around the / operator, the entire division. Let's say you indicate n = 31. n/6 Will give a result of 5 . You got then the numbers of teams you have, so your method createTeams has to have a loop of 5 iterations where you create a new ArrayList . I recommend having another dynamic structure to save every team, like another ArrayList .

Once you created your "teams", you sort your players correctly and then add them to your different teams. Here we can find the problem of duplications. Be sure to not add twice the same player by: a) Saving the hole list on an auxiliar structure where once you pick them you erase them b) Using carefully the same pointer to your initial structure representing the rooster

I think you got the idea, the methods you used are correct but you got to work on the algorithm. Good luck, any further questions feel free to ask.