TaroFillingAStringDiv2 | Topcoder Archive

Problem Statement

Cat Taro likes strings. You are given a String S. Each character of S is 'A', 'B', or '?'.

To Taro, the ugliness of a string is the number of pairs of equal consecutive characters. For example, the ugliness of "ABABAABBB" is 3: there is one pair "AA" and two (overlapping) pairs "BB".

Taro now wants to change each question mark in S either to 'A' or to 'B'. His goal is to minimize the ugliness of the resulting string. Return the smallest ugliness that can be achieved.

Definition

Class:: TaroFillingAStringDiv2
Method:: getNumber
Parameters:: String
Returns:: int
Method signature:: int getNumber(String S)
(be sure your method is public)

Constraints

S will contain between 1 and 50 characters, inclusive.
S will consist only of characters 'A', 'B' and '?'.

Examples

```
"ABAA"
```
```
Returns: 1
```
There is initially one pair of consecutive digits that are equal in this case. There is no characters that Taro has to replace, hence the answer is 1.
```
"??"
```
```
Returns: 0
```
```
"A?A"
```
```
Returns: 0
```
```
"A??B???AAB?A???A"
```
```
Returns: 3
```

"?BB?BAAB???BAB?B?AAAA?ABBA????A?AAB?BBA?A?"

Returns: 10

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