完全平方数，各位数位和为质数 ... ...B3828(in my race)!

J组冲刺比赛

1.To calculate perfect square number, we must use: $for$.

1.要计算完全平方数，我们必须使用：$for$。

bool isPSN(long long num) {
    for (long long i = 0; i < num; i++) {
        for (long long i = 0; i < num; i++) {
            if (i * j == num) return true;
        }
    }
    return false;
}

2.To get the sum of the digits is or not a prime number, use to_string and operator[] and stoi and... ...

2.要获取数字之和是否为素数，使用 to_string 和 operator[] 以及 stoi 和··· ···

bool isPrimeNumber(long long num) {
    if (number <= 1) return false;
    if (number == 2) return true;
    if (number % 2 == 0) return false;
    for (int i = 3; i <= sqrt(number); i += 2) {
        if (number % i == 0) return false;
    }
    return true;
}
bool SOTDisPN(long long num) {
    string strnum = to_string(num);
    int sum = 0;
    for (int i = 0; i < strnum.size(); i++) {
        sum += stoi(to_string(strnum[i]));
    }
    return isPrimeNumber(sum);
}

3.want solve this qestion, we need to put things together.

3.要解决这个问题，我们需要把它们放在一起。

unsigned long long l, r, ans = 0;
cin >> l >> r;
vector<int>goodnums(r - l);
for (int i = l; i < r; i++) {
    if (isPSN(i) and SOTDisPN(i)) goodnums.push_back(i);
}
if (goodnums.size() != 0) {
    ans = goodnums[0];
    for (int i = 1; i < goodnums.size(); i++) {
        ans *= goodnums[i]
    }
}
cout << ans % 998244353 << "\n";