結果

問題 No.1302 Random Tree Score
ユーザー Chanyuh
提出日時 2020-12-31 18:33:16
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 13 ms / 3,000 ms
コード長 4,516 bytes
コンパイル時間 1,245 ms
コンパイル使用メモリ 126,924 KB
最終ジャッジ日時 2025-01-17 08:47:50
ジャッジサーバーID
(参考情報)
judge2 / judge2
このコードへのチャレンジ
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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<iostream>
#include<array>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<tuple>
#include<cassert>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = 998244353;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define Per(i,sta,n) for(int i=n-1;i>=sta;i--)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};
template<class T>bool chmax(T &a, const T &b) {if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a, const T &b) {if(b<a){a=b;return 1;}return 0;}
template<int mod>
struct ModInt {
long long x;
static constexpr int MOD = mod;
ModInt() : x(0) {}
ModInt(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
explicit operator int() const {return x;}
ModInt &operator+=(const ModInt &p) {
if((x += p.x) >= mod) x -= mod;
return *this;
}
ModInt &operator-=(const ModInt &p) {
if((x += mod - p.x) >= mod) x -= mod;
return *this;
}
ModInt &operator*=(const ModInt &p) {
x = (int)(1LL * x * p.x % mod);
return *this;
}
ModInt &operator/=(const ModInt &p) {
*this *= p.inverse();
return *this;
}
ModInt operator-() const { return ModInt(-x); }
ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
ModInt operator%(const ModInt &p) const { return ModInt(0); }
bool operator==(const ModInt &p) const { return x == p.x; }
bool operator!=(const ModInt &p) const { return x != p.x; }
ModInt inverse() const{
int a = x, b = mod, u = 1, v = 0, t;
while(b > 0) {
t = a / b;
a -= t * b;
swap(a, b);
u -= t * v;
swap(u, v);
}
return ModInt(u);
}
ModInt power(long long n) const {
ModInt ret(1), mul(x);
while(n > 0) {
if(n & 1)
ret *= mul;
mul *= mul;
n >>= 1;
}
return ret;
}
ModInt power(const ModInt p) const{
return ((ModInt)x).power(p.x);
}
friend ostream &operator<<(ostream &os, const ModInt<mod> &p) {
return os << p.x;
}
friend istream &operator>>(istream &is, ModInt<mod> &a) {
long long x;
is >> x;
a = ModInt<mod>(x);
return (is);
}
};
using modint = ModInt<mod>;
struct ModFac{
public:
vector<modint> f,i_f;
int n;
ModFac(int n_){
n=n_;
f.resize(n+1,1);
i_f.resize(n+1,1);
for(int i=0;i<n;i++){
f[i+1]=f[i]*(modint)(i+1);
}
i_f[n]=f[n].power(mod-2);
for(int i=n-1;i>=0;i--){
i_f[i]=i_f[i+1]*(modint)(i+1);
}
}
ModFac(modint n_){
n=(int)n_;
f.resize(n+1,1);
i_f.resize(n+1,1);
for(int i=0;i<n;i++){
f[i+1]=f[i]*(modint)(i+1);
}
i_f[n]=f[n].power(mod-2);
for(int i=n-1;i>=0;i--){
i_f[i]=i_f[i+1]*(modint)(i+1);
}
}
modint factorial(int x){
//cout << f.size() << endl;
return f[x];
}
modint inv_factorial(int x){
return i_f[x];
}
modint comb(int m,int k){
if (m<0 or k<0) return 0;
if (m<k) return 0;
return f[m]*i_f[k]*i_f[m-k];
}
};
int n;
ModFac MF(500010);
void solve(){
cin >> n;
modint ans=0;
modint pow=1;
rep(i,n-1){
ans+=MF.comb(n,n-2-i)*pow*MF.inv_factorial(i);
pow*=n;
}
ans*=MF.factorial(n-2);
ans/=((modint)n).power(n-2);
cout << ans << endl;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cout << fixed << setprecision(50);
solve();
}
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