You have exactly 100 coins in your pocket. A kiosk that keeps no small change rounds every price to the nearest multiple of 10 and charges the rounded amount. A price that falls exactly halfway (say, 25) is rounded up (to 30). Zero counts as a multiple of 10 too.
Given the price of a purchase price, return how many coins you have left after paying.
Example 1
price=37 → 60
The nearest round number to 37 is 40, so 100 − 40 = 60 is left.
Example 2
price=65 → 30
65 is exactly halfway between 60 and 70, so it rounds up to 70. 30 is left.
Example 3
price=4 → 100
4 is closer to 0 than to 10, so the purchase costs nothing and 100 is left.