Question

我有一个ArrayList来自.dat文件的员工信息（姓名，员工分数和每个员工雇用的日期）。我正在尝试遍历ArrayList以将员工团队放在一起，以便他们的集体得分超过20.我试图通过屏蔽子集中的每个位来实现这一点。

这是.dat文件：

Francis Pelaez, 9, 3/7/1992
Marlo Frankel, 4, 4/4/2001
Suzanne Engelmann, 2, 5/20/1992
Gertrude Anderson, 5, 8/16/2009
Delmer Mickels, 3, 1/19/1994

以下是我从.dat文件中将员工加载到ArrayList中的地方：

public static ArrayList<Employee> loadEmployees() {

    ArrayList<Employee> employees = new ArrayList<Employee>();

    //load employees from employees.dat here...
    try (Scanner scanner = new Scanner(new FileInputStream("employees.dat"))) {
        while(scanner.hasNextLine()) {
            String line = scanner.nextLine();

            String[] tokens = line.split(", ");

            String fullName = tokens[0];
            String score = tokens[1];
            String dateHired = tokens[2];

            System.out.println("Full Name: " + fullName);
            System.out.println("Employee Score: " + score);
            System.out.println("Date Hired: " + dateHired);
            System.out.println("-----------------------------------");

            employees.add(new Employee(fullName, score, dateHired));
        }
        } catch (FileNotFoundException ex) {
            System.out.println("File not found: " + ex.getMessage());
        }       
    return employees;
}

这是我的saveTeams（）方法：

public static void saveTeams() {
    //load employee objects and then query them

    ArrayList<Employee> employees = loadEmployees();

    //enumerate all subsets of employees and print
    //any teams found with a collective employee
    //rating above 20   

    int allMasks = (1 << employees.size());
    for (int i = 1; i < allMasks; i++) {
        for (int j = 0; j < employees.size(); j++) {
        if ((i &(1 << j)) > 0) //the j-th element is used
            System.out.print((j + 1) + " ");
        System.out.println();
        }
    }
    }

一旦我运行saveTeams（），它似乎显示的数字组合小于我的ArayList的大小。我的问题是如何比较每个员工的得分而不是他们在ArrayList中的索引？

谢谢大家的时间。

Answer 1

如果您不介意使用Guava Collections和Java 8：

Set<Employee> employees = loadEmployees();
Sets.powerSet(employees).stream()
    .filter(es -> 20 > es.stream().map(Employee::getScore).sum())
    .collect(Collectors.toList())

枚举ArrayList

1 个答案: