#include <cstdio> long long log10(long long x) { long long l = 1; while(x >= 10) { x /= 10; ++l; } return l; } bool ok(long long n, long long k) { long long x = n, y = 0; while(x > 0) { long long z = x % 10; x /= 10; y += z * z; } return k * y == n; } int main() { long long k, a, b; scanf("%lld%lld%lld", &k, &a, &b); if(a % k != 0) a += k - (a % k); while(true) { long long l = log10(b); long long c = k * l * 9 * 9; if(b > c) b = c; else break; } long long w = 0; for(long long i = a; i <= b; i += k) if(ok(i, k)) ++w; printf("%lld\n", w); 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 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 | #include <cstdio> long long log10(long long x) { long long l = 1; while(x >= 10) { x /= 10; ++l; } return l; } bool ok(long long n, long long k) { long long x = n, y = 0; while(x > 0) { long long z = x % 10; x /= 10; y += z * z; } return k * y == n; } int main() { long long k, a, b; scanf("%lld%lld%lld", &k, &a, &b); if(a % k != 0) a += k - (a % k); while(true) { long long l = log10(b); long long c = k * l * 9 * 9; if(b > c) b = c; else break; } long long w = 0; for(long long i = a; i <= b; i += k) if(ok(i, k)) ++w; printf("%lld\n", w); return 0; } |