Prime Number Checker Using a Loop

Medium ⏱ 12 min 55% acceptance ★★★★☆ 4.4

Write a function is_prime(n) that returns True if n is a prime number and False otherwise, using a for loop that checks divisibility up to the square root of n for efficiency.

Examples

Example 1

Input

is_prime(17)

Output

True

Explanation

17 has no divisors other than 1 and itself.

Example 2

Input

is_prime(15)

Output

False

Explanation

15 = 3 * 5.

Example 3

Input

is_prime(1)

Output

False

Explanation

By definition 1 is not prime.

Constraints

n is a positive integer.

Topics

Loopsfor looploop-else

Companies

GoogleAmazon

Hints

Hint 1

Numbers less than 2 are never prime.

Hint 2

You only need to test divisors up to int(n ** 0.5) + 1 for efficiency, though testing all up to n-1 is also acceptable.

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