結果

問題 No.1392 Don't be together
コンテスト
ユーザー mugen_1337
提出日時 2021-02-12 22:48:31
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
WA  
実行時間 -
コード長 5,366 bytes
コンパイル時間 2,912 ms
コンパイル使用メモリ 202,544 KB
最終ジャッジ日時 2025-01-18 19:17:29
ジャッジサーバーID
（参考情報） 		judge5 / judge1
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 * 2 WA * 1
other AC * 1 WA * 26
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ソースコード

diff # 

#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 998244353
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

struct UnionFind{
    private:
    vector<int> par,siz;

    public:
    int con;
    UnionFind(int n):par(n),siz(n,1),con(n){
        iota(begin(par),end(par),0);
    }
    int root(int x){
        return (par[x]==x?x:(par[x]=root(par[x])));
    }
    bool sameroot(int x,int y){
        return root(x)==root(y);
    }
    bool unite(int x,int y){
        x=root(x);y=root(y);
        if(x==y) return false;
        if(siz[x]<siz[y])swap(x,y);
        siz[x]+=siz[y];
        par[y]=x;
        con--;
        return true;
    }
    int size(int x){
        return siz[root(x)];
    }
};


// graph template
// ref : https://ei1333.github.io/library/graph/graph-template.cpp
template<typename T=int>
struct Edge{
    int from,to;
    T w;
    int idx;
    Edge()=default;
    Edge(int from,int to,T w=1,int idx=-1):from(from),to(to),w(w),idx(idx){}
    operator int() const{return to;}
};

template<typename T=int>
struct Graph{
    vector<vector<Edge<T>>> g;
    int V,E;
    Graph()=default;
    Graph(int n):g(n),V(n),E(0){}

    size_t size(){
        return g.size();
    }
    void resize(int k){
        g.resize(k);
    }
    inline const vector<Edge<T>> &operator[](int k)const{
        return (g.at(k));
    }
    inline vector<Edge<T>> &operator[](int k){
        return (g.at(k));
    }
    void add_directed_edge(int from,int to,T cost=1){
        g[from].emplace_back(from,to,cost,E++);
    }
    void add_edge(int from,int to,T cost=1){
        g[from].emplace_back(from,to,cost,E);
        g[to].emplace_back(to,from,cost,E++);
    }
    void read(int m,int pad=-1,bool weighted=false,bool directed=false){
        for(int i=0;i<m;i++){
            int u,v;cin>>u>>v;
            u+=pad,v+=pad;
            T w=T(1);
            if(weighted) cin>>w;
            if(directed) add_directed_edge(u,v,w);
            else         add_edge(u,v,w);
        }
    }
};

template<ll Mod>
struct ModInt{
    long long x;
    ModInt():x(0){}
    ModInt(long long y):x(y>=0?y%Mod:(Mod-(-y)%Mod)%Mod){}
    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;}
    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;
            swap(a-=t*b,b);swap(u-=t*v,v);
        }
        return ModInt(u);
    }
    ModInt pow(long long n)const{
        ModInt ret(1),mul(x);
        while(n>0){
            if(n&1) ret*=mul;
            mul*=mul;n>>=1;
        }
        return ret;
    }
    friend ostream &operator<<(ostream &os,const ModInt &p){return os<<p.x;}
    friend istream &operator>>(istream &is,ModInt &a){long long t;is>>t;a=ModInt<Mod>(t);return (is);}
    static int get_mod(){return Mod;}
};
using mint=ModInt<998244353>;

signed main(){
    int n,m;cin>>n>>m;
    Graph<int> g(n);
    rep(i,n){
        int p;cin>>p;p--;
        g.add_edge(i,p);
    }

    vector<int> check(n,false);
    bool isnamori=true;
    int add=0;
    function<void(int,int)> namori=[&](int pre,int cur){
        int precnt=0;
        check[cur]=true;
        add++;
        for(auto e:g[cur]){
            if(e==pre) precnt++;
            else{
                if(!check[e]) namori(cur,e);
            }
        }
        if(precnt>=2) isnamori=false;
    };


    mint res=1;
    rep(i,n)if(!check[i]){
        isnamori=true;
        add=0;
        namori(-1,i);
        if(isnamori) res*=mint(m)*mint(m-1).pow(add-2)*mint(m-2);
        else         res*=mint(m)*mint(m-1).pow(add-1);

        // if(isnamori) cout<<mint(m)*mint(m-1).pow(add-2)*mint(m-2)<<endl;
        // else         cout<<mint(m)*mint(m-1).pow(add-1)<<endl;
    }
    mint fac=1;
    for(int i=1;i<=m;i++) fac*=i;
    cout<<res/fac<<endl;
    return 0;
}
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