向上调整(Java)
private void heapInsert(int[] arr, int index) {
while (arr[index] > arr[(index - 1) / 2]) {
swap(arr, index, (index - 1) / 2);
index = (index - 1) / 2;
}
}
向下调整(Java)
private void heapify(int[] arr, int index, int heapSize) {
int left = index * 2 + 1;
while (left < heapSize) {
int largest = left + 1 < heapSize && arr[left + 1] > arr[left] ? left + 1 : left;
largest = arr[largest] > arr[index] ? largest : index;
if (largest == index)
break;
swap(arr, largest, index);
index = largest;
left = index * 2 + 1;
}
}
堆排序(Java)
public void heapSort(int[] arr) {
if (arr == null || arr.length < 2)
return;
for (int i = arr.length - 1; i >= 0; i--)
heapify(arr, i, arr.length);
int heapSize = arr.length;
swap(arr, 0, --heapSize);
while (heapSize > 0) {
heapify(arr, 0, heapSize);
swap(arr, 0, --heapSize);
}
}