結果

問題 No.2068 Restricted Permutation
ユーザー 👑 potato167
提出日時 2022-09-02 21:54:03
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 10 ms / 2,000 ms
コード長 3,189 bytes
コンパイル時間 2,061 ms
コンパイル使用メモリ 199,240 KB
最終ジャッジ日時 2025-02-07 01:11:32
ジャッジサーバーID
(参考情報)
judge1 / judge3
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 * 23
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>
#pragma GCC optimize("Ofast")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const ll mod=998244353;
#define rep(i,a) for (ll i=0;i<a;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
ll jyo(ll x,ll y,ll z){
ll H=y; //
ll a=1,b=(x%z+z)%z,c=1;
while(H>0){
a*=2;
if(H%a!=0){
H-=a/2;
c*=b;
c%=z;
}
b*=b;
b%=z;
} //
return c;
}
namespace po167{
struct combination{
int upper;
long long MOD;
std::vector<long long> fact;
std::vector<long long> rev;
std::vector<long long> fact_rev;
combination(int max,long long mod):upper(max),MOD(mod),fact(max+1),rev(max+1),fact_rev(max+1){
for(long long i=0;i<=max;i++){
if(i<2){
fact[i]=1;
fact_rev[i]=1;
rev[i]=1;
continue;
}
fact[i]=(fact[i-1]*i)%mod;
rev[i]=mod-((mod/i)*rev[mod%i])%mod;
fact_rev[i]=(fact_rev[i-1]*rev[i])%mod;
}
}
long long Comb(int x,int y){
assert(upper>=x);
if (x<y||y<0||x<0) return 0;
return (((fact_rev[y]*fact_rev[x-y])%MOD)*fact[x])%MOD;
}
long long P(int x,int y){
assert(upper>=x);
if (x<y||y<0||x<0) return 0;
return (fact_rev[x-y]*fact[x])%MOD;
}
};
}
using po167::combination;
void solve();
// oddloop
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int t=1;
//cin>>t;
rep(i,t) solve();
}
void solve(){
ll N,K,X;
cin>>N>>K>>X;
X--;
combination table(N,mod);
if(N==1){
cout<<"0\n";
return;
}
ll ans=0,tmp;
rep(i,N){
//cout<<(ans*table.fact[N-1])%mod<<"\n";
if(i==K-1){
tmp=(X*(N-i-1))%mod;
tmp=(tmp*table.fact[N-i-1])%mod;
tmp=(tmp*table.rev[N-1])%mod;
ans=(ans+tmp)%mod;
}
else if(i<K){
tmp=(table.fact[N-i-1]*(((N-i-2))%mod))%mod;
tmp=(tmp*((mod+1)/2))%mod;
ans=(ans+tmp)%mod;
tmp=(table.fact[N-i-1]*(N-X-1))%mod;
tmp=(tmp*table.rev[N-1])%mod;
ans=(ans+tmp)%mod;
}
else if(i>=K){
tmp=(table.fact[N-i-1]*(((N-i-1))%mod))%mod;
tmp=(tmp*((mod+1)/2))%mod;
ans=(ans+tmp)%mod;
}
}
ans=(ans*table.fact[N-1])%mod;
cout<<ans<<"\n";
}
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