SpamChecker | Topcoder Archive

Problem Statement

Wolf Sothe was troubled with e-mail spam every day, so he decided to make his own spam filter.

Sothe's approach starts by looking at each line of the e-mail separately and classifying it either as good or bad. The more bad lines an e-mail contains, the more likely it is a spam.

Sothe already implemented the above part, and you are given its output as a String judgeLog. The characters of judgeLog correspond to the lines of an e-mail, in order. The character 'o' represents a good line and the character 'x' represents a bad line. For example, judgeLog="oxooo" corresponds to an e-mail with 5 lines. The second line of this e-mail is bad and the other four lines are good.

Sothe now came up with an algorithm to decide whether an e-mail is spam. Pseudocode of the algorithm is shown below.

At the beginning, set the score of the e-mail to 0.
For each line of the e-mail, in order:
    If the line is good, increase the score by G.
    If the line is bad, decrease the score by B.
    If the score is now negative (i.e., smaller than 0):
        Classify the e-mail as "SPAM" and terminate.
If the score was never negative:
    Classify the e-mail as "NOT SPAM" and terminate.

In the pseudocode, G and B are positive integers. You are given their values as ints good and bad.

Return "SPAM" (quotes for clarity) if the e-mail described by judgeLog is a spam, and "NOT SPAM" otherwise.

Definition

Class:: SpamChecker
Method:: spamCheck
Parameters:: String, int, int
Returns:: String
Method signature:: String spamCheck(String judgeLog, int good, int bad)
(be sure your method is public)

Constraints

judgeLog will contain between 1 and 50 characters, inclusive.
Each character in judgeLog will be 'o' or 'x'.
good will be between 1 and 1000, inclusive.
bad will be between 1 and 1000, inclusive.

Examples

```
"ooooxxxo"
```
```
2
```
```
3
```
```
Returns: "SPAM"
```
After the 7th line of this e-mail the score is 2+2+2+2-3-3-3 = -1. Hence, at that moment the e-mail gets classified as spam.
```
"ooooxxxo"
```
```
3
```
```
4
```
```
Returns: "NOT SPAM"
```
In this case, the score of the e-mail will never be negative, so it gets classified as not spam. Note that after 7 lines of this e-mail the score is 0, but that does not make it a spam.

"xooooooooooooooooooooooooooo"

Returns: "SPAM"

"oxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

Returns: "NOT SPAM"

"ooxoxoxooxoxxoxoxooxoxoxoxxoxx"

Returns: "SPAM"

"oooxoxoxoxoxoxooxooxoxooxo"

Returns: "NOT SPAM"

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