結果

問題 No.1302 Random Tree Score
ユーザー risujiroh
提出日時 2020-11-27 22:08:51
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 31 ms / 3,000 ms
コード長 4,856 bytes
コンパイル時間 2,145 ms
コンパイル使用メモリ 196,512 KB
最終ジャッジ日時 2025-01-16 07:30:36
ジャッジサーバーID
(参考情報)
judge5 / judge4
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 14
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
template <uint32_t Modulus>
class ModularInt {
using M = ModularInt;
public:
static_assert(int(Modulus) >= 1, "Modulus must be in the range [1, 2^31)");
static constexpr int modulus() { return Modulus; }
static M raw(uint32_t v) { return *reinterpret_cast<M*>(&v); }
ModularInt() : v_(0) {}
ModularInt(int64_t v) : v_((v %= Modulus) < 0 ? v + Modulus : v) {}
template <class T>
explicit operator T() const {
return v_;
}
M& operator++() { return v_ = ++v_ == Modulus ? 0 : v_, *this; }
M& operator--() { return --(v_ ? v_ : v_ = Modulus), *this; }
M operator+() const { return *this; }
M operator-() const { return raw(v_ ? Modulus - v_ : 0); }
M& operator*=(M o) { return v_ = uint64_t(v_) * o.v_ % Modulus, *this; }
M& operator/=(M o) {
auto [inv, gcd] = extgcd(o.v_, Modulus);
assert(gcd == 1);
return *this *= inv;
}
M& operator+=(M o) {
return v_ = int(v_ += o.v_ - Modulus) < 0 ? v_ + Modulus : v_, *this;
}
M& operator-=(M o) {
return v_ = int(v_ -= o.v_) < 0 ? v_ + Modulus : v_, *this;
}
friend M operator++(M& a, int) { return std::exchange(a, ++M(a)); }
friend M operator--(M& a, int) { return std::exchange(a, --M(a)); }
friend M operator*(M a, M b) { return a *= b; }
friend M operator/(M a, M b) { return a /= b; }
friend M operator+(M a, M b) { return a += b; }
friend M operator-(M a, M b) { return a -= b; }
friend std::istream& operator>>(std::istream& is, M& x) {
int64_t v;
return is >> v, x = v, is;
}
friend std::ostream& operator<<(std::ostream& os, M x) { return os << x.v_; }
friend bool operator==(M a, M b) { return a.v_ == b.v_; }
friend bool operator!=(M a, M b) { return a.v_ != b.v_; }
private:
static std::array<int, 2> extgcd(int a, int b) {
std::array x{1, 0};
while (b) std::swap(x[0] -= a / b * x[1], x[1]), std::swap(a %= b, b);
return {x[0], a};
}
uint32_t v_;
};
template <class T, class N>
constexpr T power(T a, N n) {
static_assert(std::is_integral_v<N>);
assert(n >= 0);
T res = n & 1 ? a : 1;
while (n >>= 1) {
a *= a;
if (n & 1) res *= a;
}
return res;
}
#pragma region my_template
struct Rep {
struct I {
int i;
void operator++() { ++i; }
int operator*() const { return i; }
bool operator!=(I o) const { return i < *o; }
};
const int l_, r_;
Rep(int l, int r) : l_(l), r_(r) {}
Rep(int n) : Rep(0, n) {}
I begin() const { return {l_}; }
I end() const { return {r_}; }
};
struct Per {
struct I {
int i;
void operator++() { --i; }
int operator*() const { return i; }
bool operator!=(I o) const { return i > *o; }
};
const int l_, r_;
Per(int l, int r) : l_(l), r_(r) {}
Per(int n) : Per(0, n) {}
I begin() const { return {r_ - 1}; }
I end() const { return {l_ - 1}; }
};
template <class F>
struct Fix : private F {
Fix(F f) : F(f) {}
template <class... Args>
decltype(auto) operator()(Args&&... args) const {
return F::operator()(*this, std::forward<Args>(args)...);
}
};
template <class T = int>
T scan() {
T res;
std::cin >> res;
return res;
}
template <class T, class U = T>
bool chmin(T& a, U&& b) {
return b < a ? a = std::forward<U>(b), true : false;
}
template <class T, class U = T>
bool chmax(T& a, U&& b) {
return a < b ? a = std::forward<U>(b), true : false;
}
#ifndef LOCAL
#define DUMP(...) void(0)
template <int OnlineJudge, int Local>
constexpr int OjLocal = OnlineJudge;
#endif
using namespace std;
#define ALL(c) begin(c), end(c)
#pragma endregion
using Mint = ModularInt<998244353>;
constexpr int N = 1 << 20;
auto fact = [] {
std::vector<Mint> res(N + 1);
res[0] = 1;
for (int i = 1; i <= N; ++i) res[i] = i * res[i - 1];
return res;
}();
auto ifact = [] {
std::vector<Mint> res(N + 1);
res[N] = 1 / fact[N];
for (int i = N; i--;) res[i] = res[i + 1] * (i + 1);
return res;
}();
Mint binom(int n, int k) {
assert(n <= N);
return 0 <= k and k <= n ? fact[n] * ifact[k] * ifact[n - k] : 0;
}
Mint homo(int n, int k) { return n or k ? binom(n + k - 1, k) : 1; }
auto minv = [] {
std::vector<Mint> res(N + 1);
for (int i = 1; i <= N; ++i) res[i] = ifact[i] * fact[i - 1];
return res;
}();
template <>
Mint& Mint::operator/=(Mint o) {
assert(o.v_);
return *this *= o.v_ <= N ? minv[o.v_] : extgcd(o.v_, modulus())[0];
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
cout << fixed << setprecision(20);
int n = scan();
Mint ans;
for (int k : Rep(n - 1))
ans += binom(n, k) * fact[n - 2] * ifact[n - k - 2] *
power<Mint>(n, n - k - 2);
ans /= power<Mint>(n, n - 2);
cout << ans << '\n';
}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0