Code Of The Day : Circle Of Numbers

Problem Statement 

Consider integer numbers from 0 to n - 1 written down along the circle in such a way that the distance between any two neighboring numbers is equal (note that 0 and n - 1 are neighboring, too).

Given n and firstNumber, find the number which is written in the radially opposite position to firstNumber.

Example

For n = 10 and firstNumber = 2, the output should be
circleOfNumbers(n, firstNumber) = 7.

Input/Output

• [execution time limit] 4 seconds (py3)

• [input] integer n

  A positive even integer.

  Guaranteed constraints:
  4 ≤ n ≤ 20.

• [input] integer firstNumber

  Guaranteed constraints:
  0 ≤ firstNumber ≤ n - 1.

• [output] integer

    Answer

def circleOfNumbers(n, firstNumber):

    m = (n//2 + firstNumber)

    if m >= n:

        return m-n

    else:

        return m