算法 排序 python 实现堆排序

堆排序

#!/usr/bin/python
import sys

def left_child(node):
    return node * 2 + 1

def right_child(node):
    return node * 2 + 2

def parent(node):
    if (node % 2):
        return (i - 1) / 2
    else:
        return (i - 2) / 2

def max_heapify(array, i, heap_size):
    l = left_child(i)
    r = right_child(i)

    largest = i
    if l < heap_size and array[l] > array[i]:
        largest = l

    if r < heap_size and array[r] > array[largest]:
        largest = r

    if largest != i:
        array[i], array[largest] = array[largest], array[i]
        max_heapify(array, largest, heap_size)

def build_max_heap(array):
    for i in range(len(array) / 2, -1, -1):
        max_heapify(array, i, len(array))


def heap_sort(array):
    build_max_heap(array)
    for i in range(len(array) - 1, 0, -1):
        array[0], array[i] = array[i], array[0]
        max_heapify(array, 0, i)


if __name__ == "__main__":
    array = [0, 2, 6, 98, 34, -5, 23, 11, 89, 100, 7]
    heap_sort(array)

    for a in array:
        sys.stdout.write("%d " % a)