[LeetCode]--204. Count Primes

Description:

Count the number of prime numbers less than a non-negative number, n.

Credits:
Special thanks to @mithmatt for adding this problem and creating all test cases.

public int countPrimes(int n) {
        int count = 0;
        for (int i = 2; i < n; i++)
            if (isPrime(i))
                count++;
        return count;
    }