countDivisible.md

Description: Given two integers firstNumber and secondNumber and a divisor, count the number of integers within the range [firstNumber, secondNumber] that are divisible by the divisor.

Examples

Example 1:

Input: firstNumber = 6, secondNumber = 11, divisor = 2 Output: 3

Example 2:

Input: firstNumber = 0, secondNumber = 0, divisor = 11 Output: 1

Example 3:

Input: firstNumber = 10, secondNumber = 10, divisor = 5 Output: 1

Example 4:

Input: firstNumber = 10, secondNumber = 10, divisor = 7 Output: 0

Algorithmic Steps This problem is solved using simple arithmetic:

1. Compute the number of divisible numbers up to secondNumber by dividing it by the divisor and taking the floor.
2. Compute the number of divisible numbers before firstNumber by dividing (firstNumber - 1) by the divisor and taking the floor.
3. Subtract the two results to get the count of divisible numbers in the range.

Time and Space complexity:

• Time complexity: O(1).
• Space complexity: O(1).