Count of Prime Numbers till N - DSA Practice

You are given an integer n. You need to find out the number of prime numbers in the range [1, n] (inclusive). Return the number of prime numbers in the range.

A prime number is a number which has no divisors except, 1 and itself.

Example 1:

Input: n = 6

Output: 3

Explanation: Prime numbers in the range [1, 6] are 2, 3, 5.

Example 2:

Input: n = 10

Output: 4

Explanation: Prime numbers in the range [1, 10] are 2, 3, 5, 7.

Now Your Turn!

Pick the correct output for the given input

Input: n = 20

19798

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Constraints:

2 <= n <= 1000