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Competition Arena > TippingWaiters
SRM 270 · 2005-11-03 · by misof · Brute Force, Simple Math
Class Name: TippingWaiters
Return Type: int
Method Name: possiblePayments
Arg Types: (int, int)
Problem Statement

Problem Statement

In a restaurant, if you were pleased by the waiter's service, you may leave him a tip -- you pay him more than the actual value of the bill, and the waiter keeps the excess money. In some countries, not leaving a tip for the waiter is even considered impolite. During my recent holiday I was having dinner in a foreign restaurant. The pamphlet from my travel agency informed me that the proper way of tipping the waiter is the following:
  • The sum I pay must be round, i.e., divisible by 5.
  • The tip must be between 5% and 10% of the final sum I pay, inclusive.
Clearly, sometimes there may be multiple "correct" ways of settling the bill. I'd like to know exactly how many choices I have in a given situation. I could program it easily, but I was having a holiday... and so it's you who has to solve this task. You will be given:
  • an int bill -- the amount I have to pay for the dinner
  • an int cash -- the amount of money I have in my pocket
Write a function that computes how many different final sums satisfy the conditions above.

Notes

  • Assume that both bill and cash are in dollars.
  • All the money I have is in one-dollar banknotes.

Constraints

  • bill and cash are between 1 and 2,000,000,000, inclusive.
  • bill doesn't exceed cash.
Examples
0)
4
100
Returns: 0

4 isn't a round sum, and 5 is too much.

1)
23
100
Returns: 1

The only correct choice is to pay 25 dollars, thus leaving a tip of 2 dollars.

2)
23
24
Returns: 0

The same bill, but I don't have enough money to leave an appropriate tip.

3)
220
239
Returns: 1

This time, it is appropriate to pay either 235 or 240 dollars. Sadly, I don't have enough money for the second possibility.

4)
1234567
12345678
Returns: 14440

A large bill, but with that much money I don't care.

Submissions are judged against all 51 archived test cases, of which 5 are shown here. Case numbers match the judge’s.

Coding Area

Language: C++17 · define a public class TippingWaiters with a public method int possiblePayments(int bill, int cash) · 51 test cases · 2 s / 256 MB per case

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