LeetCode 204. Count Primes

class Solution {
public:
    int countPrimes(int n) {
        if (n <= 1) {
            return 0;
        }
        int nums[n];
        for (int i = 0; i < n; i++) {
            nums[i] = 1;
        }
        nums[0] = 0;nums[1] = 0;
        for (int i = 2; i * i <= n; i++) {
            if (!nums[i]) {
                continue;
            }
            for (int j = 2; i * j < n; j++) {
                nums[i * j] = 0;
            }
        }
        int solve = 0;
        for (int i = 0; i < n; i++) {
            solve += nums[i];
        }
        return solve;
    }
};