如何在Java中使用PriorityQueue<int[]>对包含3个值的数组进行排序?

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英文:

How to sort with PriorityQueue<int[]> 3-values in Java?

问题

我正尝试使用 `PriorityQueue``Comparator` 进行排序但我不知道如何编写方法

如果第三个元素相同则我希望将其与第一个元素进行比较如果第一个元素也相同则我希望将其与第二个元素进行比较

我尝试在比较方法中编写如下

```java
if (o1[2] < o2[2])
    return 1;
else if (o1[2] > o2[2])
    return -1;
return 0;

但不起作用... 请帮帮我...

Queue<int[]> q = new PriorityQueue<int[]>(new Comparator<int[]>() {
    @Override
    public int compare(int[] o1, int[] o2) {
        if (o1[2] == o2[2]) {
            if (o1[0] == o2[0]) {
                return Integer.compare(o1[1], o2[1]);
            } else {
                return Integer.compare(o1[0], o2[0]);
            }
        } else {
            return Integer.compare(o2[2], o1[2]);
        }
    }
});

q.add(new int[] {2, 2, 2});
q.add(new int[] {2, 4, 2});
q.add(new int[] {3, 3, 2});
q.add(new int[] {3, 1, 2});
q.add(new int[] {2, 7, 1});
q.add(new int[] {4, 7, 1});

我想要获取排序后的队列 Queue<int[]> 数据:

2 7 1
4 7 1
2 2 2
2 4 2
3 1 2
3 3 2
英文:

I am trying to sort with PriorityQueue and Comparator, but I don't know how to write method..

If third element is the same, I want to compare it to the first element. If the first element is also the same, i want to compare it to the second element.

I tried to write in compare method :

if(o1[2]&lt;o2[2])
 return 1;
else if(o1[2]&gt;o2[2])
 return -1;
return 0;

but not working.. plz hele me...

Queue&lt;int[]&gt; q = new PriorityQueue&lt;int[]&gt;(new Comparator&lt;int[]&gt;() {
	@Override
	public int compare(int[] o1, int[] o2) {
		return 0;
	}
});

q.add(new int[] {2, 2, 2});
q.add(new int[] {2, 4, 2});
q.add(new int[] {3, 3, 2});
q.add(new int[] {3, 1, 2});
q.add(new int[] {2, 7, 1});
q.add(new int[] {4, 7, 1});

I want to get Queue<int> datas

2 7 1

4 7 1

2 2 2

2 4 2

3 1 2

3 3 2

答案1

得分: 0

使用数组的不同部分进行比较。如果得到差异,返回该差异,以便进行排序。如果没有得到差异,使用另一个数组索引进行另一次比较。因此,在您的情况下,对于third -> first -> second,使用索引2、0,然后1。

public int compare(int[] o1, int[] o2) {
    int out = compareUsingIndex(2, o1, o2);
    if (out != 0) {
        return out;
    }
    out = compareUsingIndex(0, o1, o2);
    if (out != 0) {
        return out;
    }
    return compareUsingIndex(1, o1, o2);
}

private int compareUsingIndex(int index, int[] o1, int[] o2) {
    if (o1[index] == o2[index]) {
        return 0;
    } else if (o1[index] > o2[index]) {
        return 1;
    }
    return -1;
}
英文:

Do your comparison using different parts of the array. If you get a difference, return it, which allows sorting. If you don't get a difference, do another comparison using another array index. So in your case for third -> first -> second, use indexes 2, 0 and then 1.

    public int compare(int[] o1, int[] o2) {
        int out = compareUsingIndex (2, o1, o2);
        if (out !=0){
            return out;
        }
        out = compareUsingIndex (0, o1, o2);
        if (out !=0){
            return out;
        }
        return compareUsingIndex (1, o1, o2);
    }
    
    private int compareUsingIndex(int index, int[] o1, int[] o2){
        if (o1[index]==o2[index]){
           return 0;
         }
        else if (o1[index]&gt;o2[index]){
           return 1;
         }
        return -1;
    }

huangapple
  • 本文由 发表于 2020年10月16日 14:52:16
  • 转载请务必保留本文链接:https://go.coder-hub.com/64384247.html
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