#include #include #include #include using namespace std; bool is_prime(int a) { if (a < 4) { if (a == 1) {return false;} else {return true;} } else if (a % 2 == 0) { return false; } for (int i = 3; i < sqrt(a) + 2; i+=2) { if (a % i == 0) {return false;} } return true; } int sum_digit(int a) { int x = a; int sum = 0; for (int i = 0; i < 6; i++) { sum += x % 10; x /= 10; } return sum; } int frank_hash(int a) { int sum = a; for (;sum > 9;) { sum = sum_digit(sum); } return sum; } void output(vector a) { int l = a.size(); cout << "["; for (int i = 0; i < l; i++) { cout << a[i] << ", "; } cout << "]" << endl; } int main(void) { int K, N; cin >> K >> N; cout << sum_digit(K) << endl; cout << frank_hash(K) << endl; int maxfirst; int maxlen = 0; int curlen = 0; vector ps, hs; for (int i = K; i < N + 1; i++) { if (!is_prime(i)) {continue;} int h = frank_hash(i); bool is_exest = false; for (int j = 0; j < hs.size(); j++) { if (hs[j] == h) { if (curlen >= maxlen) { maxlen = curlen; maxfirst = ps[0]; } curlen -= j + 1; ps.erase(ps.begin(), ps.begin() + j + 1); hs.erase(hs.begin(), hs.begin() + j + 1); is_exest = true; break; } } ps.push_back(i); hs.push_back(h); curlen++; //cout << i << ", " << h << ", " << curlen << ", " << maxlen << ", " << maxfirst << endl; //output(ps); //output(hs); } if (curlen >= maxlen) { maxlen = curlen; maxfirst = ps[0]; } //cout << "max first: " << maxfirst << ", max len: " << maxlen << endl; cout << maxfirst << endl; return 0; }