AccountBalanceAfterRoundedPurchase.py

# Initially, you have a bank account balance of 100 dollars.
# You are given an integer purchaseAmount representing the amount you will spend on a purchase in dollars.
# At the store where you will make the purchase, the purchase amount is rounded to the nearest multiple of 10. In other words, you pay a non-negative amount, roundedAmount, such that roundedAmount is a multiple of 10 and abs(roundedAmount - purchaseAmount) is minimized.
# If there is more than one nearest multiple of 10, the largest multiple is chosen.
# Return an integer denoting your account balance after making a purchase worth purchaseAmount dollars from the store.
# Note: 0 is considered to be a multiple of 10 in this problem.

import math

def accountBalanceAfterPurchase(purchaseAmount):
    ones = (purchaseAmount % 10) / 10
    tens = purchaseAmount // 10 

    if ones < 0.5:
        ones = math.floor(ones)
    else:
        ones = math.ceil(ones)

    return 100 - ((tens + ones) * 10)

# Test cases
purchaseAmount = 9
print(accountBalanceAfterPurchase(purchaseAmount))

purchaseAmount = 15
print(accountBalanceAfterPurchase(purchaseAmount))

purchaseAmount = 5
print(accountBalanceAfterPurchase(purchaseAmount))