如何将单个地图条目添加到优先级队列 [英] How to add a single map entry to priority queue

问题描述

目前我必须添加整个地图，如最后一行所示.

At the moment I have to add the whole map, as shown in the last line.

PriorityQueue<Map.Entry<String, Integer>> sortedCells = new PriorityQueue<Map.Entry<String, Integer>>(3, new mem());
    Map<String,Integer> pn = new HashMap<String,Integer>();
    pn.put("hello", 1);
    pn.put("bye", 3);
    pn.put("goodbye", 8);
    sortedCells.addAll(pn.entrySet());

如果我只想添加怎么办

("word" 5)

如果我这样做

sortedCells.add("word",5)

我收到一个参数错误.

如何添加单个元素?

推荐答案

你应该添加一个 Map.Entry 对象而不仅仅是 ("word", 5) 因为您的优先级队列的通用类型是 Map.Entry.在这种情况下，您可能应该创建自己的 Map.Entry 类:

You should add a Map.Entry object and not just ("word", 5) because the generic type of your priority queue is Map.Entry<String, Integer>. In this case you should probably create your own Map.Entry class:

final class MyEntry implements Map.Entry<String, Integer> {
    private final String key;
    private Integer value;

    public MyEntry(String key, Integer value) {
        this.key = key;
        this.value = value;
    }

    @Override
    public String getKey() {
        return key;
    }

    @Override
    public Integer getValue() {
        return value;
    }

    @Override
    public Integer setValue(Integer value) {
        Integer old = this.value;
        this.value = value;
        return old;
    }
}

在您的代码中，您现在可以调用:

In your code you can now call:

sortedCells.add(new MyEntry("word",5));

如果您不想实现自己的条目，可以使用 AbstractMap.SimpleEntry:

If you don't want to implement your own entry you could use AbstractMap.SimpleEntry:

sortedCells.add(new AbstractMap.SimpleEntry<String, Integer>("word",5));

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