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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#772681 | #9553. The Hermit | Clarus | WA | 0ms | 3612kb | C++20 | 5.6kb | 2024-11-22 21:11:10 | 2024-11-22 21:11:10 |
Judging History
answer
#include <bits/stdc++.h>
using LL = long long;
constexpr int inf = 1E9;
template<class T>
constexpr T power(T a, LL b)
{
T res = 1;
while (b > 0)
{
if (b & 1)
{
res *= a;
}
b >>= 1;
a *= a;
}
return res;
}
template<int P>
struct MInt
{
int x;
static int Mod;
constexpr MInt() : x{} {}
constexpr MInt(LL x) : x{norm(x % getMod())} {}
constexpr static int getMod()
{
if (P) return P;
else return Mod;
}
constexpr static void setMod(int mod)
{
Mod = mod;
}
constexpr int norm(int x) const
{
if (x < 0)
{
x += getMod();
}
if (x >= getMod())
{
x -= getMod();
}
return x;
}
constexpr int val() const
{
return x;
}
explicit constexpr operator int() const
{
return x;
}
constexpr MInt operator-() const
{
MInt res;
res.x = norm(getMod() - x);
return res;
}
constexpr MInt inv() const
{
assert(x != 0);
return power(*this, getMod() - 2);
}
constexpr MInt &operator*=(MInt rhs) &
{
x = 1LL * x * rhs.x % getMod();
return *this;
}
constexpr MInt &operator+=(MInt rhs) &
{
x = norm(x + rhs.x);
return *this;
}
constexpr MInt &operator-=(MInt rhs) &
{
x = norm(x - rhs.x);
return *this;
}
constexpr MInt &operator/=(MInt rhs) &
{
return *this *= rhs.inv();
}
constexpr MInt &operator++() &
{
x = norm(x + 1);
return *this;
}
constexpr MInt operator++(int)
{
MInt temp = *this;
++(*this);
return temp;
}
friend constexpr MInt operator*(MInt lhs, MInt rhs)
{
MInt res = lhs;
res *= rhs;
return res;
}
friend constexpr MInt operator+(MInt lhs, MInt rhs)
{
MInt res = lhs;
res += rhs;
return res;
}
friend constexpr MInt operator-(MInt lhs, MInt rhs)
{
MInt res = lhs;
res -= rhs;
return res;
}
friend constexpr MInt operator/(MInt lhs, MInt rhs)
{
MInt res = lhs;
res /= rhs;
return res;
}
friend constexpr std::istream &operator>>(std::istream &is, MInt &a)
{
LL v;
is >> v;
a = MInt(v);
return is;
}
friend constexpr std::ostream &operator<<(std::ostream &os, const MInt &a)
{
return os << a.val();
}
friend constexpr bool operator<(MInt lhs, MInt rhs)
{
return lhs.val() < rhs.val();
}
friend constexpr bool operator==(MInt lhs, MInt rhs)
{
return lhs.val() == rhs.val();
}
friend constexpr bool operator!=(MInt lhs, MInt rhs)
{
return lhs.val() != rhs.val();
}
};
template<>
int MInt<0>::Mod = int(1e9) + 7;
template<int V, int P>
constexpr MInt<P> inv = MInt<P>(V).inv();
constexpr int P = 998244353;
using Z = MInt<P>;
namespace comb
{
int n = 0;
std::vector<Z> _fac{1}, _invfac{1}, _inv{0};
void init(int m)
{
m = std::min(m, Z::getMod() - 1);
if (m <= n) return;
_fac.resize(m + 1);
_invfac.resize(m + 1);
_inv.resize(m + 1);
for (int i = n + 1; i <= m; i++)
{
_fac[i] = _fac[i - 1] * i;
}
_invfac[m] = _fac[m].inv();
for (int i = m; i > n; i--)
{
_invfac[i - 1] = _invfac[i] * i;
_inv[i] = _invfac[i] * _fac[i - 1];
}
n = m;
}
Z fac(int m)
{
if (m > n) init(2 * m);
return _fac[m];
}
Z invfac(int m)
{
if (m > n) init(2 * m);
return _invfac[m];
}
Z inv(int m)
{
if (m > n) init(2 * m);
return _inv[m];
}
Z binom(int n, int m)
{
if (n < m || m < 0) return 0;
return fac(n) * invfac(m) * invfac(n - m);
}
}
std::vector<int> minp, primes;
void sieve(int n)
{
minp.assign(n + 1, 0);
primes.clear();
for (int i = 2; i <= n; i++)
{
if (minp[i] == 0)
{
minp[i] = i;
primes.emplace_back(i);
}
for (auto p : primes)
{
if (i * p > n)
{
break;
}
minp[i * p] = p;
if (p == minp[i])
{
break;
}
}
}
}
int main()
{
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
int n, m;
std::cin >> m >> n;
sieve(m);
std::vector<int> a(m + 1), b(m + 1);
for (int i = 1; i <= m; i++)
{
b[i] = (m - i) / i;
a[i] = 1;
int j = i;
for (auto p : primes)
{
int c = 0;
while (j % p == 0)
{
c++;
j /= p;
}
a[i] *= (c + 1);
if (j == 1) { break; }
}
a[i]--;
}
Z ans = comb::binom(m, n) * n;
for (int i = 1; i <= m; i++)
{
int l = n - 1 - std::min(n - 1, b[i]);
int r = std::min(n - 1, a[i]);
for (int j = l; j <= r; j++)
{
Z sub = comb::binom(a[i], j) * comb::binom(b[i], n - 1 - j);
ans -= sub;
}
}
std::cout << ans << '\n';
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 3612kb
input:
4 3
output:
7
result:
ok 1 number(s): "7"
Test #2:
score: -100
Wrong Answer
time: 0ms
memory: 3440kb
input:
11 4
output:
1185
result:
wrong answer 1st numbers differ - expected: '1187', found: '1185'