DSA/heapsort.py

#!/usr/bin/env python3

import sys
import math

def heap_sort(A):
    heap_build_max_heap(A)

    print("Initial heap:")
    heap_print(A, len(A))
    print()

    for i in range(len(A)-1, 0, -1):
        A[0], A[i] = A[i], A[0]
        heap_max_heapify(A, i)

        print("\nNew heap: length =", i)
        heap_print(A, i)
        print()

def heap_max_heapify(A, size):
    if size < 2:
        return

    print("size =", size)
    i = 0

    left = heap_left(size, i)
    print("left =", left)

    while left is not None:
        right = heap_right(size, i)
        print("right =", right)

        if right is None:
            if A[i] < A[left]:
                A[i], A[left] = A[left], A[i]
            break

        ma = max_3(A[i], A[left], A[right])
        if ma == A[i]:
            break
        elif ma == A[left]:
            A[i], A[left] = A[left], A[i]
            i = left
        else:
            A[i], A[right] = A[right], A[i]
            i = right

        left = heap_left(size, i)
        print("left =", left)


def heap_build_max_heap(A):
    if len(A) < 2:
        return
    for i in range(math.ceil(len(A)/2), 1, -1):
        heap_max_heapify(A, i)


def heap_print(A, size):
    i = 1
    newline = False
    while i <= size:
        print(A[i-1], end='\t')
        newline = False
        i = i + 1
        if is_power_2(i):
            print()
            newline = True
    if not newline:
        print()


def is_power_2(n):
    while n > 1:
        if n % 2 == 1:
            return False
        n = n // 2
    return True


def max_3(a, b, c):
    if a > b:
        if a > c:
            return a
        else:
            return c
    else:
        if b > c:
            return b
        else:
            return c


def heap_parent(n):
    n = n + 1
    if n == 1:
        return None
    else:
        return (n // 2) - 1


def heap_left(size, n):
    n = n + 1
    l = n * 2
    if l > size:
        return None
    else:
        return l - 1


def heap_right(size, n):
    n = n + 1
    l = n * 2 + 1
    if l > size:
        return None
    else:
        return l - 1


if __name__ == "__main__":
    args = [int(x) for x in sys.argv[1:]]
    heap_sort(args)
    print(args)