Question

如何在具有7个数字的简单基本Java伪代码中初始化堆数据结构？

Answer 1

如果您想自己动手而不使用Java的PriorityQueue，那么您必须将所有X项放在正确的位置，以便它们支持堆属性：

//This will switch the current item with it's greatest child, if this child is
//larger than the current item itself.
private void percolateDown(int i){
    //Get n's greatest child. The two children are at position 2i+1 and 2i+2
    int n = getGreatestChild(i);

    //Don't do anything if the greater child is smaller or equal to the parent
    if( yourNumbersArray[n] <= yourNumbersArray[i] )
        return;

    //Now switch the parent with the greatest child

    //Make sure that the newly placed item is at the right spot by percolating it again.
    percolateDown(n);
}

private void initialize(){
    //Call the percolateDown() function for all items of your array.
    //Due to the heap nature you can leave out the second half, though. 
    int mid = yourNumbersArray.length/2;

//Start in the middle and work your way towards the front.
//This way you'll first sort the lowest level of your heap, then the second lowest, and so on.
    for(; mid>=0; --mid){
        percolateDown(mid);
    }
}

在寻找任何物品中最伟大的孩子时，你必须记住，一个或两个孩子可能在你的阵列之外。在这种情况下，您当然不必考虑它。

Answer 2

使用PriorityQueue。它以Heap DS实现。

然后简单地使用queue.add（yourObject）;

添加

默认情况下，它使用自然排序，如果您还需要其他任何内容，则可以使用自己的Comparator。

初始化堆数据结构java

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