def swap(i, j):
    sqc[i], sqc[j] = sqc[j], sqc[i]
 
def heapify(end,i):
    l=3 * (i + 1)
    m=3 * (i + 2)
    r=3 * (i + 3)
    max=i
    if l < end and sqc[i] < sqc[l]:
        max = l
    if r < end and sqc[max] < sqc[r]:
        max = r
    if m < end and sqc[max] < sqc[m]:
        max = m
    if max != i:
        swap(i, max)
        heapify(end, max)
 
def heap_sort():
    end = len(sqc)
    start = end / 2 - 1
    for i in range(start, -1, -1):
        heapify(end, i)
    for i in range(end-1, 0, -1):
        swap(i, 0)
        heapify(i, 0)
 
sqc = [2, 7, 1, -2, 56, 5, 3]
heap_sort()
print(sqc)

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