PowerDigit | Topcoder Archive

Problem Statement

We need to know the k-th digit in x to the power y. A value of 0 for k means that the digit of interest is the rightmost digit, a value of 1 means the digit next to the rightmost digit, etc.

Create a class PowerDigit that contains a method digitK that is given x, y, and k and that returns the k-th digit (an integer in the range 0 to 9 inclusive) in x to the power y. If there is no k-th digit in x to the power y return -1.

Definition

Class:: PowerDigit
Method:: digitK
Parameters:: int, int, int
Returns:: int
Method signature:: int digitK(int x, int y, int k)
(be sure your method is public)

Constraints

x is between 0 and 10,000, inclusive.
y is between 1 and 10,000, inclusive.
k is between 0 and 4, inclusive.

Examples

```
2
```
```
10
```
```
1
```
```
Returns: 2
```
2^10 = 1024 so the digit 1 is 2.
```
2
```
```
10
```
```
4
```
```
Returns: -1
```
1024 does not have a digit 4 (the 1 in 1024 is digit 3)
```
2
```
```
1000
```
```
0
```
```
Returns: 6
```
2^1000 is a very large number. But digit 0 is predictable since with succeeding powers it follows the sequence 2, 4, 8, 6, 2, 4, 8, 6, 2, ....
```
9999
```
```
10000
```
```
4
```
```
Returns: 0
```

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