simple-fun-181-rounding.md

Simple Fun #181: Rounding ^{7 Kyu}

^{LINK TO THE KATA - FUNDAMENTALS}

Description

Round the given number n to the nearest multiple of m.

If n is exactly in the middle of 2 multiples of m, return n instead.

Example

For n = 20, m = 3, the output should be 21.

For n = 19, m = 3, the output should be 18.

For n = 50, m = 100, the output should be 50.

Input/Output

• [input] integer n
1 ≤ n < 10^9.

• [input] integer m
3 ≤ m < 109.

• [output] an integer
  

Solution

const rounding = (n, m) => {
  const lowerMultiple = n - (n % m)
  const upperMultiple = lowerMultiple + m

  if (n - lowerMultiple === upperMultiple - n) return n

  return n - lowerMultiple < upperMultiple - n ? lowerMultiple : upperMultiple
}