Вот кое-что, с чего можно начать. Этот короткий аль go будет сортировать людей на основе указанного дискриминатора (национальность, пол и т. Д. c.), А затем равномерно распределять их по указанному количеству групп.
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Function;
import java.util.stream.Collectors;
public class Main {
private static class Person {
private String nationality;
private String gender;
public Person(String nationality, String gender) {
this.nationality = nationality;
this.gender = gender;
}
public String getNationality() {
return nationality;
}
public String getGender() {
return gender;
}
@Override
public String toString() {
return "Person{" +
"nationality='" + nationality + "'" +
", gender='" + gender + "'" +
"}";
}
}
public static void main(String[] args) {
List<Person> people = Arrays.asList(
new Person("DE", "male"),
new Person("DE", "female"),
new Person("DE", "n/a"),
new Person("UK", "female"),
new Person("UK", "female"),
new Person("UK", "female"),
new Person("JP", "trans"),
new Person("JP", "male")
);
int number_of_groups = 3;
Function<Person, String> discriminator = Person::getGender;
AtomicInteger index = new AtomicInteger();
List<List<Person>> groups = new ArrayList<>(people.stream()
.sorted(Comparator.comparing(discriminator))
.collect(Collectors.groupingBy(e -> index.getAndIncrement() % number_of_groups))
.values());
groups.forEach(System.out::println);
}
}
Вывод:
[Person{nationality='DE', gender='female'}, Person{nationality='UK', gender='female'}, Person{nationality='JP', gender='trans'}]
[Person{nationality='UK', gender='female'}, Person{nationality='DE', gender='male'}]
[Person{nationality='UK', gender='female'}, Person{nationality='DE', gender='n/a'}]