#3233
Find the Count of Numbers Which Are Not Special
medium · 27.5% accepted · 197 likes · top 5%
array · math · number theory
Description
You are given 2 positive integers l and r. For any number x, all positive divisors of x except x are called the proper divisors of x.
A number is called special if it has exactly 2 proper divisors. For example:
- The number 4 is special because it has proper divisors 1 and 2.
- The number 6 is not special because it has proper divisors 1, 2, and 3.
Return the count of numbers in the range [l, r] that are not special.
Solution