https://www.interviewcake.com/question/product-of-other-numbers

products.py

def get_products_of_all_ints_except_at_index(int_array):
    """
    Single pass.
    """

    # Condition where element has neither left nor right elements
    if len(int_array) == 1:
        # Maybe [None] ?
        return [0]

    left_product = 1
    right_product = 1

    products = [1] * len(int_array)  # init array

    for left_index in xrange(len(int_array)):
        right_index = len(int_array) - 1 - left_index

        products[left_index] *= left_product
        products[right_index] *= right_product

        if left_index == 0:
            left_product = int_array[left_index]
            right_product = int_array[right_index]
        else:
            left_product *= int_array[left_index]
            right_product *= int_array[right_index]

    return products

print get_products_of_all_ints_except_at_index([3, 1, 2, 6, 5, 9]) # [540, 1620, 810, 270, 324, 180]
print get_products_of_all_ints_except_at_index([1, 7, 3, 4])       # [84, 12, 28, 21]
print get_products_of_all_ints_except_at_index([1])                # [0]
print get_products_of_all_ints_except_at_index([])                 # []