Task: Top rank per group
C++: #include <string>
#include <set>
#include <list>
#include <map>
#include <iostream>


struct Employee
{
    std::string Name;
    std::string ID;
    unsigned long Salary;
    std::string Department;
    Employee(std::string _Name = "", std::string _ID = "", unsigned long _Salary = 0, std::string _Department = "")
    : Name(_Name), ID(_ID), Salary(_Salary), Department(_Department)
    { }

    void display(std::ostream& out) const
    {
        out << Name << "\t" << ID << "\t" << Salary << "\t" << Department << std::endl;
    }
};


struct CompareEarners
{
    bool operator()(const Employee& e1, const Employee& e2)
    {
        return (e1.Salary > e2.Salary);
    }
};


typedef std::list<Employee> EMPLOYEELIST;



typedef std::set<Employee, CompareEarners> DEPARTMENTPAYROLL;

typedef std::map<std::string, DEPARTMENTPAYROLL> DEPARTMENTLIST;

void initialize(EMPLOYEELIST& Employees)
{
    
    Employees.push_back(Employee("Tyler Bennett", "E10297", 32000, "D101"));
    Employees.push_back(Employee("John Rappl", "E21437", 47000, "D050"));
    Employees.push_back(Employee("George Woltman", "E21437", 53500, "D101"));
    Employees.push_back(Employee("Adam Smith", "E21437", 18000, "D202"));
    Employees.push_back(Employee("Claire Buckman", "E39876", 27800, "D202"));
    Employees.push_back(Employee("David McClellan", "E04242", 41500, "D101"));
    Employees.push_back(Employee("Rich Holcomb", "E01234", 49500, "D202"));
    Employees.push_back(Employee("Nathan Adams", "E41298", 21900, "D050"));
    Employees.push_back(Employee("Richard Potter", "E43128", 15900, "D101"));
    Employees.push_back(Employee("David Motsinger", "E27002", 19250, "D202"));
    Employees.push_back(Employee("Tim Sampair", "E03033", 27000, "D101"));
    Employees.push_back(Employee("Kim Arlich", "E10001", 57000, "D190"));
    Employees.push_back(Employee("Timothy Grove", "E16398", 29900, "D190"));
}

void group(EMPLOYEELIST& Employees, DEPARTMENTLIST& Departments)
{
    
    for( EMPLOYEELIST::iterator iEmployee = Employees.begin();
         Employees.end() != iEmployee;
         ++iEmployee )
    {
        DEPARTMENTPAYROLL& groupSet = Departments[iEmployee->Department];

        
        groupSet.insert(*iEmployee);
    }
}

void present(DEPARTMENTLIST& Departments, unsigned int N)
{
    
    for( DEPARTMENTLIST::iterator iDepartment = Departments.begin();
         Departments.end() != iDepartment;
         ++iDepartment )
    {
        std::cout << "In department " << iDepartment->first << std::endl;
        std::cout << "Name\t\tID\tSalary\tDepartment" << std::endl;
        
        unsigned int rank = 1;
        for( DEPARTMENTPAYROLL::iterator iEmployee = iDepartment->second.begin();
             ( iDepartment->second.end() != iEmployee) && (rank <= N);
             ++iEmployee, ++rank )
        {
            iEmployee->display(std::cout);
        }
        std::cout << std::endl;
    }
}

int main(int argc, char* argv[])
{
    
    EMPLOYEELIST Employees;

    
    initialize(Employees);

    
    DEPARTMENTLIST Departments;

    
    
    group(Employees, Departments);

    
    present(Departments, 3);

    return 0;
}

Java: import java.io.File;
import java.util.*;

public class TopRankPerGroup {

    private static class Employee {
        final String name;
        final String id;
        final String department;
        final int salary;

        Employee(String[] rec) {
            name = rec[0];
            id = rec[1];
            salary = Integer.parseInt(rec[2]);
            department = rec[3];
        }

        @Override
        public String toString() {
            return String.format("%s %s %d %s", id, name, salary, department);
        }
    }

    public static void main(String[] args) throws Exception {
        int N = args.length > 0 ? Integer.parseInt(args[0]) : 3;

        Map<String, List<Employee>> records = new TreeMap<>();
        try (Scanner sc = new Scanner(new File("data.txt"))) {
            while (sc.hasNextLine()) {
                String[] rec = sc.nextLine().trim().split(", ");

                List<Employee> lst = records.get(rec[3]);
                if (lst == null) {
                    lst = new ArrayList<>();
                    records.put(rec[3], lst);
                }
                lst.add(new Employee(rec));
            }
        }

        records.forEach((key, val) -> {
            System.out.printf("%nDepartment %s%n", key);
            val.stream()
                .sorted((a, b) -> Integer.compare(b.salary, a.salary))
                .limit(N).forEach(System.out::println);
        });
    }
}