QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#281746 | #4812. Counting Sequence | zhangmj2008 | AC ✓ | 6419ms | 17464kb | C++17 | 17.2kb | 2023-12-10 17:26:04 | 2023-12-10 17:26:05 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
typedef long long ll; typedef unsigned long long ull;
const int INF = 1e9; const ll LLNF = 4e18;
template< class Tp > void chkmax( Tp &x , Tp y ) { x = max( x , y ); }
template< class Tp > void chkmin( Tp &x , Tp y ) { x = min( x , y ); }
namespace atcoder {
namespace internal {
// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
int x = 0;
while ((1U << x) < (unsigned int)(n)) x++;
return x;
}
// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
unsigned long index;
_BitScanForward(&index, n);
return index;
#else
return __builtin_ctz(n);
#endif
}
} // namespace internal
} // namespace atcoder
namespace atcoder {
namespace internal {
#ifndef _MSC_VER
template <class T>
using is_signed_int128 =
typename std::conditional<std::is_same<T, __int128_t>::value ||
std::is_same<T, __int128>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_unsigned_int128 =
typename std::conditional<std::is_same<T, __uint128_t>::value ||
std::is_same<T, unsigned __int128>::value,
std::true_type,
std::false_type>::type;
template <class T>
using make_unsigned_int128 =
typename std::conditional<std::is_same<T, __int128_t>::value,
__uint128_t,
unsigned __int128>;
template <class T>
using is_integral = typename std::conditional<std::is_integral<T>::value ||
is_signed_int128<T>::value ||
is_unsigned_int128<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_signed_int = typename std::conditional<(is_integral<T>::value &&
std::is_signed<T>::value) ||
is_signed_int128<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_unsigned_int =
typename std::conditional<(is_integral<T>::value &&
std::is_unsigned<T>::value) ||
is_unsigned_int128<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using to_unsigned = typename std::conditional<
is_signed_int128<T>::value,
make_unsigned_int128<T>,
typename std::conditional<std::is_signed<T>::value,
std::make_unsigned<T>,
std::common_type<T>>::type>::type;
#else
template <class T> using is_integral = typename std::is_integral<T>;
template <class T>
using is_signed_int =
typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using is_unsigned_int =
typename std::conditional<is_integral<T>::value &&
std::is_unsigned<T>::value,
std::true_type,
std::false_type>::type;
template <class T>
using to_unsigned = typename std::conditional<is_signed_int<T>::value,
std::make_unsigned<T>,
std::common_type<T>>::type;
#endif
template <class T>
using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;
template <class T>
using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;
template <class T> using to_unsigned_t = typename to_unsigned<T>::type;
} // namespace internal
} // namespace atcoder
namespace atcoder {
namespace internal {
// @param m `1 <= m`
// @return x mod m
constexpr long long safe_mod(long long x, long long m) {
x %= m;
if (x < 0) x += m;
return x;
}
// Fast modular multiplication by barrett reduction
// Reference: https://en.wikipedia.org/wiki/Barrett_reduction
// NOTE: reconsider after Ice Lake
struct barrett {
unsigned int _m;
unsigned long long im;
// @param m `1 <= m < 2^31`
barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}
// @return m
unsigned int umod() const { return _m; }
// @param a `0 <= a < m`
// @param b `0 <= b < m`
// @return `a * b % m`
unsigned int mul(unsigned int a, unsigned int b) const {
// [1] m = 1
// a = b = im = 0, so okay
// [2] m >= 2
// im = ceil(2^64 / m)
// -> im * m = 2^64 + r (0 <= r < m)
// let z = a*b = c*m + d (0 <= c, d < m)
// a*b * im = (c*m + d) * im = c*(im*m) + d*im = c*2^64 + c*r + d*im
// c*r + d*im < m * m + m * im < m * m + 2^64 + m <= 2^64 + m * (m + 1) < 2^64 * 2
// ((ab * im) >> 64) == c or c + 1
unsigned long long z = a;
z *= b;
#ifdef _MSC_VER
unsigned long long x;
_umul128(z, im, &x);
#else
unsigned long long x =
(unsigned long long)(((unsigned __int128)(z)*im) >> 64);
#endif
unsigned int v = (unsigned int)(z - x * _m);
if (_m <= v) v += _m;
return v;
}
};
// @param n `0 <= n`
// @param m `1 <= m`
// @return `(x ** n) % m`
constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
if (m == 1) return 0;
unsigned int _m = (unsigned int)(m);
unsigned long long r = 1;
unsigned long long y = safe_mod(x, m);
while (n) {
if (n & 1) r = (r * y) % _m;
y = (y * y) % _m;
n >>= 1;
}
return r;
}
// Reference:
// M. Forisek and J. Jancina,
// Fast Primality Testing for Integers That Fit into a Machine Word
// @param n `0 <= n`
constexpr bool is_prime_constexpr(int n) {
if (n <= 1) return false;
if (n == 2 || n == 7 || n == 61) return true;
if (n % 2 == 0) return false;
long long d = n - 1;
while (d % 2 == 0) d /= 2;
constexpr long long bases[3] = {2, 7, 61};
for (long long a : bases) {
long long t = d;
long long y = pow_mod_constexpr(a, t, n);
while (t != n - 1 && y != 1 && y != n - 1) {
y = y * y % n;
t <<= 1;
}
if (y != n - 1 && t % 2 == 0) {
return false;
}
}
return true;
}
template <int n> constexpr bool is_prime = is_prime_constexpr(n);
// @param b `1 <= b`
// @return pair(g, x) s.t. g = gcd(a, b), xa = g (mod b), 0 <= x < b/g
constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {
a = safe_mod(a, b);
if (a == 0) return {b, 0};
// Contracts:
// [1] s - m0 * a = 0 (mod b)
// [2] t - m1 * a = 0 (mod b)
// [3] s * |m1| + t * |m0| <= b
long long s = b, t = a;
long long m0 = 0, m1 = 1;
while (t) {
long long u = s / t;
s -= t * u;
m0 -= m1 * u; // |m1 * u| <= |m1| * s <= b
// [3]:
// (s - t * u) * |m1| + t * |m0 - m1 * u|
// <= s * |m1| - t * u * |m1| + t * (|m0| + |m1| * u)
// = s * |m1| + t * |m0| <= b
auto tmp = s;
s = t;
t = tmp;
tmp = m0;
m0 = m1;
m1 = tmp;
}
// by [3]: |m0| <= b/g
// by g != b: |m0| < b/g
if (m0 < 0) m0 += b / s;
return {s, m0};
}
// Compile time primitive root
// @param m must be prime
// @return primitive root (and minimum in now)
constexpr int primitive_root_constexpr(int m) {
if (m == 2) return 1;
if (m == 167772161) return 3;
if (m == 469762049) return 3;
if (m == 754974721) return 11;
if (m == 998244353) return 3;
int divs[20] = {};
divs[0] = 2;
int cnt = 1;
int x = (m - 1) / 2;
while (x % 2 == 0) x /= 2;
for (int i = 3; (long long)(i)*i <= x; i += 2) {
if (x % i == 0) {
divs[cnt++] = i;
while (x % i == 0) {
x /= i;
}
}
}
if (x > 1) {
divs[cnt++] = x;
}
for (int g = 2;; g++) {
bool ok = true;
for (int i = 0; i < cnt; i++) {
if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) {
ok = false;
break;
}
}
if (ok) return g;
}
}
template <int m> constexpr int primitive_root = primitive_root_constexpr(m);
} // namespace internal
} // namespace atcoder
namespace atcoder {
namespace internal {
struct modint_base {};
struct static_modint_base : modint_base {};
template <class T> using is_modint = std::is_base_of<modint_base, T>;
template <class T> using is_modint_t = std::enable_if_t<is_modint<T>::value>;
} // namespace internal
template <int m, std::enable_if_t<(1 <= m)>* = nullptr>
struct static_modint : internal::static_modint_base {
using mint = static_modint;
public:
static constexpr int mod() { return m; }
static mint raw(int v) {
mint x;
x._v = v;
return x;
}
static_modint() : _v(0) {}
template <class T, internal::is_signed_int_t<T>* = nullptr>
static_modint(T v) {
long long x = (long long)(v % (long long)(umod()));
if (x < 0) x += umod();
_v = (unsigned int)(x);
}
template <class T, internal::is_unsigned_int_t<T>* = nullptr>
static_modint(T v) {
_v = (unsigned int)(v % umod());
}
static_modint(bool v) { _v = ((unsigned int)(v) % umod()); }
unsigned int val() const { return _v; }
mint& operator++() {
_v++;
if (_v == umod()) _v = 0;
return *this;
}
mint& operator--() {
if (_v == 0) _v = umod();
_v--;
return *this;
}
mint operator++(int) {
mint result = *this;
++*this;
return result;
}
mint operator--(int) {
mint result = *this;
--*this;
return result;
}
mint& operator+=(const mint& rhs) {
_v += rhs._v;
if (_v >= umod()) _v -= umod();
return *this;
}
mint& operator-=(const mint& rhs) {
_v -= rhs._v;
if (_v >= umod()) _v += umod();
return *this;
}
mint& operator*=(const mint& rhs) {
unsigned long long z = _v;
z *= rhs._v;
_v = (unsigned int)(z % umod());
return *this;
}
mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }
mint operator+() const { return *this; }
mint operator-() const { return mint() - *this; }
mint pow(long long n) const {
assert(0 <= n);
mint x = *this, r = 1;
while (n) {
if (n & 1) r *= x;
x *= x;
n >>= 1;
}
return r;
}
mint inv() const {
if (prime) {
assert(_v);
return pow(umod() - 2);
} else {
auto eg = internal::inv_gcd(_v, m);
assert(eg.first == 1);
return eg.second;
}
}
friend mint operator+(const mint& lhs, const mint& rhs) {
return mint(lhs) += rhs;
}
friend mint operator-(const mint& lhs, const mint& rhs) {
return mint(lhs) -= rhs;
}
friend mint operator*(const mint& lhs, const mint& rhs) {
return mint(lhs) *= rhs;
}
friend mint operator/(const mint& lhs, const mint& rhs) {
return mint(lhs) /= rhs;
}
friend bool operator==(const mint& lhs, const mint& rhs) {
return lhs._v == rhs._v;
}
friend bool operator!=(const mint& lhs, const mint& rhs) {
return lhs._v != rhs._v;
}
private:
unsigned int _v;
static constexpr unsigned int umod() { return m; }
static constexpr bool prime = internal::is_prime<m>;
};
template <int id> struct dynamic_modint : internal::modint_base {
using mint = dynamic_modint;
public:
static int mod() { return (int)(bt.umod()); }
static void set_mod(int m) {
assert(1 <= m);
bt = internal::barrett(m);
}
static mint raw(int v) {
mint x;
x._v = v;
return x;
}
dynamic_modint() : _v(0) {}
template <class T, internal::is_signed_int_t<T>* = nullptr>
dynamic_modint(T v) {
long long x = (long long)(v % (long long)(mod()));
if (x < 0) x += mod();
_v = (unsigned int)(x);
}
template <class T, internal::is_unsigned_int_t<T>* = nullptr>
dynamic_modint(T v) {
_v = (unsigned int)(v % mod());
}
dynamic_modint(bool v) { _v = ((unsigned int)(v) % mod()); }
unsigned int val() const { return _v; }
mint& operator++() {
_v++;
if (_v == umod()) _v = 0;
return *this;
}
mint& operator--() {
if (_v == 0) _v = umod();
_v--;
return *this;
}
mint operator++(int) {
mint result = *this;
++*this;
return result;
}
mint operator--(int) {
mint result = *this;
--*this;
return result;
}
mint& operator+=(const mint& rhs) {
_v += rhs._v;
if (_v >= umod()) _v -= umod();
return *this;
}
mint& operator-=(const mint& rhs) {
_v += mod() - rhs._v;
if (_v >= umod()) _v -= umod();
return *this;
}
mint& operator*=(const mint& rhs) {
_v = bt.mul(_v, rhs._v);
return *this;
}
mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }
mint operator+() const { return *this; }
mint operator-() const { return mint() - *this; }
mint pow(long long n) const {
assert(0 <= n);
mint x = *this, r = 1;
while (n) {
if (n & 1) r *= x;
x *= x;
n >>= 1;
}
return r;
}
mint inv() const {
auto eg = internal::inv_gcd(_v, mod());
assert(eg.first == 1);
return eg.second;
}
friend mint operator+(const mint& lhs, const mint& rhs) {
return mint(lhs) += rhs;
}
friend mint operator-(const mint& lhs, const mint& rhs) {
return mint(lhs) -= rhs;
}
friend mint operator*(const mint& lhs, const mint& rhs) {
return mint(lhs) *= rhs;
}
friend mint operator/(const mint& lhs, const mint& rhs) {
return mint(lhs) /= rhs;
}
friend bool operator==(const mint& lhs, const mint& rhs) {
return lhs._v == rhs._v;
}
friend bool operator!=(const mint& lhs, const mint& rhs) {
return lhs._v != rhs._v;
}
private:
unsigned int _v;
static internal::barrett bt;
static unsigned int umod() { return bt.umod(); }
};
template <int id> internal::barrett dynamic_modint<id>::bt = 998244353;
using modint998244353 = static_modint<998244353>;
using modint1000000007 = static_modint<1000000007>;
using modint = dynamic_modint<-1>;
namespace internal {
template <class T>
using is_static_modint = std::is_base_of<internal::static_modint_base, T>;
template <class T>
using is_static_modint_t = std::enable_if_t<is_static_modint<T>::value>;
template <class> struct is_dynamic_modint : public std::false_type {};
template <int id>
struct is_dynamic_modint<dynamic_modint<id>> : public std::true_type {};
template <class T>
using is_dynamic_modint_t = std::enable_if_t<is_dynamic_modint<T>::value>;
} // namespace internal
} // namespace atcoder
using modint = atcoder::modint998244353;
void solve( ) {
int n; cin >> n; int c; cin >> c;
int S = ( int ) sqrt( 2 * n ); modint ans = 0;
vector< vector< modint > > f( 2 * S + 1 , vector< modint >( 2 * S + 1 ) );
for( int a1 = 1; a1 <= S; a1 ++ ) f[a1][a1 % ( 2 * S + 1 )] = 1;
for( int j = 0; j <= n; j ++ ) {
if( j >= 2 * S + 1 ) for( int i = 1; i <= 2 * S; i ++ ) f[i][j % ( 2 * S + 1 )] = 0;
for( int i = 1; i <= 2 * S; i ++ ) if( j >= i ) {
if( i - 1 >= 1 ) f[i][j % ( 2 * S + 1 )] += f[i - 1][( j - i ) % ( 2 * S + 1 )];
if( i + 1 <= 2 * S ) f[i][j % ( 2 * S + 1 )] += c * f[i + 1][( j - i ) % ( 2 * S + 1 )];
}
if( j == n ) for( int i = 1; i <= 2 * S; i ++ ) ans += f[i][n % ( 2 * S + 1 )];
}
int mov = S * ( S - 1 ) / 2;
vector< modint > g( 2 * mov + 1 ); g[0 + mov] = 1;
for( int k = 1; k <= S; k ++ ) {
for( int j = -mov; j <= mov; j ++ ) { int a1 = ( n - j ) / k; if( a1 > S && a1 * k + j == n ) ans += g[j + mov]; }
vector< modint > ng( 2 * mov + 1 );
for( int j = -mov; j <= mov; j ++ ) {
if( j - k >= -mov ) ng[j + mov] += g[j - k + mov];
if( j + k <= mov ) ng[j + mov] += c * g[j + k + mov];
}
g = ng;
}
cout << ans.val( ) << "\n";
}
int main( ) {
ios::sync_with_stdio( 0 ), cin.tie( 0 ), cout.tie( 0 );
int T = 1; while( T -- ) solve( ); return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 3560kb
input:
5 3
output:
8
result:
ok 1 number(s): "8"
Test #2:
score: 0
Accepted
time: 0ms
memory: 3556kb
input:
1 0
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 3ms
memory: 3640kb
input:
2022 39
output:
273239559
result:
ok 1 number(s): "273239559"
Test #4:
score: 0
Accepted
time: 0ms
memory: 3596kb
input:
1 998244352
output:
1
result:
ok 1 number(s): "1"
Test #5:
score: 0
Accepted
time: 0ms
memory: 3560kb
input:
1 12345678
output:
1
result:
ok 1 number(s): "1"
Test #6:
score: 0
Accepted
time: 0ms
memory: 3556kb
input:
20 998998
output:
643731701
result:
ok 1 number(s): "643731701"
Test #7:
score: 0
Accepted
time: 0ms
memory: 3620kb
input:
23 123
output:
947753998
result:
ok 1 number(s): "947753998"
Test #8:
score: 0
Accepted
time: 0ms
memory: 3556kb
input:
50 5555
output:
745339864
result:
ok 1 number(s): "745339864"
Test #9:
score: 0
Accepted
time: 0ms
memory: 3636kb
input:
60 6666
output:
690992218
result:
ok 1 number(s): "690992218"
Test #10:
score: 0
Accepted
time: 0ms
memory: 3580kb
input:
100 50
output:
169678588
result:
ok 1 number(s): "169678588"
Test #11:
score: 0
Accepted
time: 1ms
memory: 3580kb
input:
500 88888
output:
216149701
result:
ok 1 number(s): "216149701"
Test #12:
score: 0
Accepted
time: 0ms
memory: 3672kb
input:
1000 213456
output:
270989457
result:
ok 1 number(s): "270989457"
Test #13:
score: 0
Accepted
time: 3ms
memory: 3888kb
input:
2000 119988
output:
756425375
result:
ok 1 number(s): "756425375"
Test #14:
score: 0
Accepted
time: 3ms
memory: 3956kb
input:
3000 998244352
output:
71841227
result:
ok 1 number(s): "71841227"
Test #15:
score: 0
Accepted
time: 6ms
memory: 4000kb
input:
3000 555555555
output:
79880116
result:
ok 1 number(s): "79880116"
Test #16:
score: 0
Accepted
time: 10ms
memory: 3752kb
input:
4321 1234
output:
949603993
result:
ok 1 number(s): "949603993"
Test #17:
score: 0
Accepted
time: 12ms
memory: 3956kb
input:
5000 0
output:
5
result:
ok 1 number(s): "5"
Test #18:
score: 0
Accepted
time: 12ms
memory: 3984kb
input:
5000 88888777
output:
833064960
result:
ok 1 number(s): "833064960"
Test #19:
score: 0
Accepted
time: 9ms
memory: 3760kb
input:
5000 35557777
output:
696388498
result:
ok 1 number(s): "696388498"
Test #20:
score: 0
Accepted
time: 34ms
memory: 3804kb
input:
10000 123456
output:
434296902
result:
ok 1 number(s): "434296902"
Test #21:
score: 0
Accepted
time: 97ms
memory: 4156kb
input:
20000 555555
output:
34806915
result:
ok 1 number(s): "34806915"
Test #22:
score: 0
Accepted
time: 176ms
memory: 4632kb
input:
30000 777888999
output:
58443551
result:
ok 1 number(s): "58443551"
Test #23:
score: 0
Accepted
time: 389ms
memory: 5504kb
input:
50000 2
output:
90102905
result:
ok 1 number(s): "90102905"
Test #24:
score: 0
Accepted
time: 645ms
memory: 6528kb
input:
70000 77998866
output:
202638568
result:
ok 1 number(s): "202638568"
Test #25:
score: 0
Accepted
time: 1141ms
memory: 7812kb
input:
100000 998244352
output:
360520717
result:
ok 1 number(s): "360520717"
Test #26:
score: 0
Accepted
time: 1137ms
memory: 7784kb
input:
100000 555555555
output:
613886009
result:
ok 1 number(s): "613886009"
Test #27:
score: 0
Accepted
time: 2130ms
memory: 10344kb
input:
150000 233333
output:
381065878
result:
ok 1 number(s): "381065878"
Test #28:
score: 0
Accepted
time: 2129ms
memory: 10204kb
input:
150000 20050117
output:
269891864
result:
ok 1 number(s): "269891864"
Test #29:
score: 0
Accepted
time: 3328ms
memory: 12552kb
input:
200000 114514
output:
262861613
result:
ok 1 number(s): "262861613"
Test #30:
score: 0
Accepted
time: 3322ms
memory: 12644kb
input:
200000 1919810
output:
77872388
result:
ok 1 number(s): "77872388"
Test #31:
score: 0
Accepted
time: 6256ms
memory: 17384kb
input:
300000 0
output:
12
result:
ok 1 number(s): "12"
Test #32:
score: 0
Accepted
time: 6296ms
memory: 17292kb
input:
300000 1
output:
298803948
result:
ok 1 number(s): "298803948"
Test #33:
score: 0
Accepted
time: 6269ms
memory: 17384kb
input:
300000 2
output:
106751203
result:
ok 1 number(s): "106751203"
Test #34:
score: 0
Accepted
time: 6327ms
memory: 17264kb
input:
300000 1234
output:
427045479
result:
ok 1 number(s): "427045479"
Test #35:
score: 0
Accepted
time: 6332ms
memory: 17464kb
input:
300000 2345
output:
441593553
result:
ok 1 number(s): "441593553"
Test #36:
score: 0
Accepted
time: 6234ms
memory: 17304kb
input:
300000 20041115
output:
580367993
result:
ok 1 number(s): "580367993"
Test #37:
score: 0
Accepted
time: 6313ms
memory: 17380kb
input:
300000 20050117
output:
579859619
result:
ok 1 number(s): "579859619"
Test #38:
score: 0
Accepted
time: 6261ms
memory: 17316kb
input:
300000 22223333
output:
596066085
result:
ok 1 number(s): "596066085"
Test #39:
score: 0
Accepted
time: 6372ms
memory: 17304kb
input:
300000 175846372
output:
660364393
result:
ok 1 number(s): "660364393"
Test #40:
score: 0
Accepted
time: 6419ms
memory: 17280kb
input:
299999 9999999
output:
954865020
result:
ok 1 number(s): "954865020"
Test #41:
score: 0
Accepted
time: 6379ms
memory: 17288kb
input:
299998 55556666
output:
904862432
result:
ok 1 number(s): "904862432"
Test #42:
score: 0
Accepted
time: 3045ms
memory: 12132kb
input:
190733 31756136
output:
880544587
result:
ok 1 number(s): "880544587"
Test #43:
score: 0
Accepted
time: 3220ms
memory: 12640kb
input:
198497 463488298
output:
185220207
result:
ok 1 number(s): "185220207"
Test #44:
score: 0
Accepted
time: 6302ms
memory: 17344kb
input:
299997 0
output:
16
result:
ok 1 number(s): "16"
Test #45:
score: 0
Accepted
time: 2533ms
memory: 10976kb
input:
168168 296157813
output:
798716760
result:
ok 1 number(s): "798716760"
Test #46:
score: 0
Accepted
time: 1431ms
memory: 8580kb
input:
114514 1919810
output:
783513290
result:
ok 1 number(s): "783513290"