TippingWaiters | Topcoder Archive

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.

Definition

Class:: TippingWaiters
Method:: possiblePayments
Parameters:: int, int
Returns:: int
Method signature:: int possiblePayments(int bill, int cash)
(be sure your method is public)

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

```
4
```
```
100
```
```
Returns: 0
```
4 isn't a round sum, and 5 is too much.
```
23
```
```
100
```
```
Returns: 1
```
The only correct choice is to pay 25 dollars, thus leaving a tip of 2 dollars.
```
23
```
```
24
```
```
Returns: 0
```
The same bill, but I don't have enough money to leave an appropriate tip.
```
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.
```
1234567
```
```
12345678
```
```
Returns: 14440
```
A large bill, but with that much money I don't care.
```
1880000000
```
```
1980000000
```
```
Returns: 210527
```
```
171000000
```
```
179999999
```
```
Returns: 0
```

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