DAY 48 OF 90 · Know when to stop

Is it prime

Medium90 Days of Looping

Inputs

n is a whole number from 0 to 400.

Your tasks

If n is less than 2, return false.
Use a loop over each whole number d from 2 up while d * d is at most n. If d divides n evenly, return false right away.
If the loop ends without finding a divisor, n is prime.
Complete isPrime so it returns true or false. Return it, do not print it.

Example

With n = 13, isPrime returns true.

Rules

0 and 1 are not prime.

Test data

TEST DATA 1: n is 13

TEST DATA 2: n is 1

Practice focus

While loops and early exits, for when you don't know how many rounds you need. Binary search, the Euclidean algorithm and graph search are all while loops with a clear stopping rule.

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