Facebook coding challenge

facebook_solution.py

level = [
    [10000,0.1],
    [20000,0.2],
    [10000,0.1],
    [None, 0.4]
]

def calculate_tax(level, income):
    if income <= 0:
        return (0, 0)

    if level[0] is None:
        return (0, income * level[1])
    
    if income > level[0]:
        income = income - level[0]
        return (income, level[0] * level[1])
    else:
        return (0, income * level[1])
    

def calculate(level, income):

    total_tax = 0.0
    for l in level:
        income, tax = calculate_tax(l, income)
        total_tax += tax
    return total_tax

incomes = [-1, 0, 10, 10000, 15000.75, 21000, 41000, 50000] 
taxes = [calculate(level, income) for income in incomes]       

print(taxes)
# [0.0, 0.0, 1.0, 1000.0, 2000.15, 3200.0, 6400.0, 10000.0]