#include <iostream> #include <algorithm> using namespace std; typedef long long ll; const ll FN_MAX = 20*9*9; ll k, a, b; ll do_fn(ll n) { ll res = 0; while (n) { ll d = n % 10; res += d*d; n /= 10; } return res; } int main() { cin >> k >> a >> b; int ans = 0; for (ll fn = min(b / k, FN_MAX); fn * k >= a; fn--) { if (fn * k > b) continue; ll n = fn * k; if (do_fn(n) == fn) ans++; // cout << "fn=" << fn << endl; } cout << ans << '\n'; return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | #include <iostream> #include <algorithm> using namespace std; typedef long long ll; const ll FN_MAX = 20*9*9; ll k, a, b; ll do_fn(ll n) { ll res = 0; while (n) { ll d = n % 10; res += d*d; n /= 10; } return res; } int main() { cin >> k >> a >> b; int ans = 0; for (ll fn = min(b / k, FN_MAX); fn * k >= a; fn--) { if (fn * k > b) continue; ll n = fn * k; if (do_fn(n) == fn) ans++; // cout << "fn=" << fn << endl; } cout << ans << '\n'; return 0; } |