Question

我的程序的功能是允许用户使用堆来管理任务列表。当前任务基于最快的截止日期。任务对象包含2个字符串，一个名称和一个截止日期。将任务节点添加到堆中没有问题。我的问题是它应该将它添加到堆中，并且它应该在到期日到期时成为当前任务。每当我不添加任何内容时，我的程序就能完美运行，只有当我添加一个任务时，无论我将截止日期设置为什么，新任务都成为最后一个任务。以下是一些例子：

Do Math Homework, 05/04/2015 11:00 // Read in from text file and added to heap
Do Grocery Shopping, 05/03/2015 12:00 // Read in from text file and added to heap
Write Code, 04/30/2015 15:00 
// User is asked for input and wants to add "Write Code" to Tasklist, notice the date.

Output when I run program:
Do Grocery Shopping, 05/03/2015 12:00 // This is correct order
Do Math Homework, 05/04/2015 11:00 // This is correct order
Write Code, 04/30/2015 15:00 // Problem here
// The added task always gets output last no matter what the date is

主类：

public static Heap addTask( Heap h ){
    Task newTask = new Task( "", "" ); // Create a new empty task.

    Scanner input = new Scanner(System.in);
    System.out.println("Enter the Task Name: ");
    newTask.setName( input.nextLine() );
    System.out.println("Enter the Due Date: ");
    newTask.setDueDate( input.nextLine() );

    Node n = new Node( newTask ); // Sets the data of new task and adds to Node.
    h.addNode( n );
    return h;
}

任务类：

public class Task {
    private String name;
    private String dueDate;
    public Task( String n, String d ){
    name = n;
    dueDate = d;
}
// Maybe my compareTo() is wrong?
public int compareTo( Task t ){
    return dueDate.compareTo( t.getDueDate() );
}

堆类：

public class Heap {
private ArrayList<Node> heap;
public Heap(){
    heap = new ArrayList<Node>();
}
public int getPLoc( int i ){
    return ( i - 1 ) / 2;
}
public Node getNodeAt( int i ){
    if( heap.get(i) == null ){
        System.out.println("Item does not exist.");
        return null;
    }else{
        return heap.get(i);
    }
}
public void addNode( Node n ){
    heap.add(null);
    int index = heap.size() - 1;
    while( index > 0 && getNodeAt(getPLoc(index)).getData().compareTo( n.getData() ) > 0 ){
        heap.set(index, getNodeAt(getPLoc(index)));
        index = getPLoc(index);
    }
    heap.set(index, n);
}

节点没有按时间顺序添加到堆中

0 个答案: