AlphaDice | Topcoder Archive

Problem Statement

A six-sided die has each of its sides labeled with a distinct letter. We repeatedly roll it and record the result. We can only see three sides, so each roll is recorded as a String of 3 letters, denoting the labels on the visible sides in the order top,front,right.

 
        ______   
       / A   /| 
      /_____/ | 
      |     |C|  
      | B   | /   
      |_____|/

For the above roll, we should record "ABC"

We want to check the data for consistency -- we know that the data recording process is error-prone. Create a class AlphaDice that contains a method badData that is given a String[] roll giving the recorded data, and that returns the (0-based) index of the first entry in roll that, when combined with its predecessors, is inconsistent.

If all the roll data are consistent with some distinct labeling of the die, return -1.

Definition

Class:: AlphaDice
Method:: badData
Parameters:: String[]
Returns:: int
Method signature:: int badData(String[] roll)
(be sure your method is public)

Constraints

roll will contain between 1 and 50 elements inclusive
each element of roll will have length 3 and will contain only 'A'-'Z'

Examples

```
{"ABC","ZCB"}
```
```
Returns: -1
```
This is the example above where there is a Z on the bottom. On the second roll the die was oriented so the Z was on the top, the C at the front, and the B on our right. These data are consistent with a distinctly labeled die.
```
{"ABC","DEF","BCA","GHI","ABC"}
```
```
Returns: 3
```
The first 3 were consistent with a die with 6 distinct labels, but the "GHI" must be bad data since we could not possibly observe more than 6 different labels.
```
{"ABA","CDE","CDE","CDE","CDE"}
```
```
Returns: 0
```
The first observation shows two sides labeled with 'A'
```
{"ABC","DEF","BCF"}
```
```
Returns: 2
```

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