在Matlab中使用Java PriorityQueue [英] Using Java PriorityQueue in Matlab

问题描述

我在Matlab中需要最小化堆，并且正在尝试使用Java的PriorityQueue.我被困在如何提供比较器上. 到目前为止，我已经初始化了PriorityQueue并可以向其中添加一个值-索引对:

I need a min-heap in Matlab and I'm trying to use Java's PriorityQueue. I'm stuck on how to supply the Comparator. So far I have initialized the PriorityQueue and can add one value-index pair to it:

>> q = java.util.PriorityQueue
q =
[]
>> q.add({1,3})
ans =
     1

当我尝试添加更多数据时出现问题:

The problem occurs when I try to add more data:

>> q.add({2,4})
??? Java exception occurred: 
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to java.lang.Comparable
    at java.util.PriorityQueue.siftUpComparable(Unknown Source)
    at java.util.PriorityQueue.siftUp(Unknown Source)
    at java.util.PriorityQueue.offer(Unknown Source)
    at java.util.PriorityQueue.add(Unknown Source)

从此帖子中，我看到我需要提供比较器功能，但我不知道该怎么做.

From this post, I see that I need to supply a Comparator function, but I don't know how to do this.

推荐答案

优先级队列要么包含实现Comparable的对象，要么需要在构造时传递Comparator函数.

Priority queues need to either contain objects that implement Comparable, or you need to pass in a Comparator function at construction time.

MATLAB当前没有一种方法可以用MATLAB代码实现Java接口，也不能提供文字Java代码.

There isn't a way currently in MATLAB to either implement Java interfaces with MATLAB code, or supply literal Java code.

因此，您必须遵循@nibot的建议，并制作一个小的.jar文件，其中包含实现Comparator的类.

So you'd have to follow @nibot's suggestion and make a small .jar file containing a class implementing Comparator.

这篇关于在Matlab中使用Java PriorityQueue的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！