genbio groupings haha

Main.java

package com.github.brickwall2900;

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        List<Person> people = readPeople();
        List<List<Person>> groups = group(people);
        for (int i = 0; i < groups.size(); i++) {
            System.out.printf("Group %d%n", i + 1);
            List<Person> group = groups.get(i);
            for (Person person : group) {
                System.out.printf("    - %s, %s %s%n", person.name.last, person.name.first, person.name.middle);
            }
        }
    }

    public static List<List<Person>> group(List<Person> people) {
        // okay 5 groups in total
        // equal number of boys and girls in groupings
        // so 3 boys and 4 girls per group
        // except 1 group that is 3 boys and 5 girls
        int totalGroups = 5;
        int boysPerGroup = (int) (people.stream().filter(p -> p.gender == Gender.BOY).count() / totalGroups);
        int girlsPerGroup = (int) (people.stream().filter(p -> p.gender == Gender.GIRL).count() / totalGroups);

        List<Person> boysOnly = new ArrayList<>(people.stream().filter(p -> p.gender == Gender.BOY).toList());
        List<Person> girlsOnly = new ArrayList<>(people.stream().filter(p -> p.gender == Gender.GIRL).toList());
        List<List<Person>> groups = new ArrayList<>();

        Random random = new Random();
        for (int i = 0; i < totalGroups; i++) {
            List<Person> group = new ArrayList<>();
            for (int b = 0; b < boysPerGroup; b++) {
                int rIndex = random.nextInt(0, boysOnly.size());
                group.add(boysOnly.remove(rIndex));
            }

            for (int g = 0; g < girlsPerGroup; g++) {
                int rIndex = random.nextInt(0, girlsOnly.size());
                group.add(girlsOnly.remove(rIndex));
            }
            groups.add(group);
        }

        // any remainders?
        // pick random group then join
        while (!boysOnly.isEmpty()) {
            int rGroupIndex = random.nextInt(0, groups.size());
            List<Person> group = groups.get(rGroupIndex);
            group.add(boysOnly.removeFirst());
        }

        while (!girlsOnly.isEmpty()) {
            int rGroupIndex = random.nextInt(0, groups.size());
            List<Person> group = groups.get(rGroupIndex);
            group.add(girlsOnly.removeFirst());
        }

        return groups;
    }

    public static List<Person> readPeople() {
        List<Person> people = new ArrayList<>();
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(
                new BufferedInputStream(Objects.requireNonNull(Main.class.getResourceAsStream("/people.txt")))))) {
            String line;
            while ((line = reader.readLine()) != null) {
                String[] split = line.split("\\|");
                String realName = split[0];
                String genderString = split[1];

                // find gender
                Gender gender = null;
                for (Gender availableGender : Gender.values()) {
                    if (genderString.toUpperCase(Locale.ROOT).equals(availableGender.name())) {
                        gender = availableGender;
                        break;
                    }
                }
                Objects.requireNonNull(gender, "tf");

                // parse name
                // LastName, FirstName1 FirstName2 MiddleName
                int firstComma = realName.indexOf(',');
                String lastName = realName.substring(0, firstComma);
                // next to firstComma is a space
                // find until the last word
                // tokenize
                String[] nameSplit = realName.split("\\s+");
                int lastWordIndex = nameSplit.length - 1;
                String middleInitial = nameSplit[lastWordIndex];
                int middleInitialStart = realName.indexOf(middleInitial);
                String firstName = realName.substring(firstComma + 1, middleInitialStart).trim();
                Name name = new Name(firstName, middleInitial, lastName);
                people.add(new Person(name, gender));
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return people;
    }

    enum Gender {
        BOY, GIRL;
    }

    public record Name(String first, String middle, String last) {}
    public record Person(Name name, Gender gender) {}
}