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Competition Arena > PowerDigit

PowerDigit

TCO06 Sponsor 2 · 2006-03-01 · by dgoodman

TCO06 Sponsor 2 · 2006-03-01 · by dgoodman · Math
Class Name: PowerDigit
Return Type: int
Method Name: digitK
Arg Types: (int, int, int)
Problem Statement

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.

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
0)
2
10
1
Returns: 2

2^10 = 1024 so the digit 1 is 2.

1)
2
10
4
Returns: -1

1024 does not have a digit 4 (the 1 in 1024 is digit 3)

2)
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, ....

3)
10
2
1
Returns: 0
4)
10
10
1
Returns: 0

Submissions are judged against all 119 archived test cases, of which 5 are shown here. Case numbers match the judge’s.

Coding Area

Language: C++17 · define a public class PowerDigit with a public method int digitK(int x, int y, int k) · 119 test cases · 2 s / 256 MB per case

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