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CountDiv (Lesson 5)

Instructions​

Write a function:

function solution(A, B, K);

that, given three integers A, B and K, returns the number of integers within the range [A..B] that are divisible by K, i.e.:

{ i : A ≤ i ≤ B, i mod K = 0 }

For example, for A = 6, B = 11 and K = 2, your function should return 3, because there are three numbers divisible by 2 within the range [6..11], namely 6, 8 and 10.

Write an efficient algorithm for the following assumptions:

  • A and B are integers within the range [0..2,000,000,000];
  • K is an integer within the range [1..2,000,000,000];
  • A ≤ B.

Solution​

function solution(A, B, K) {
  return Math.floor(B / K) - Math.floor((A - 1) / K);
}

Review​

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References​