結果

問題 No.2531 Coloring Vertices on Namori
ユーザー dyktr_06dyktr_06
提出日時 2023-11-03 23:24:28
言語 C++17(gcc12)
(gcc 12.3.0 + boost 1.87.0)
結果
AC  
実行時間 186 ms / 2,000 ms
コード長 11,370 bytes
コンパイル時間 2,592 ms
コンパイル使用メモリ 218,884 KB
実行使用メモリ 36,176 KB
最終ジャッジ日時 2024-09-25 21:29:28
合計ジャッジ時間 7,563 ms
ジャッジサーバーID
（参考情報） 		judge4 / 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 * 3
other AC * 31
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 # 

#include <bits/stdc++.h>

using namespace std;

#define overload4(_1, _2, _3, _4, name, ...) name
#define rep1(n) for(int i = 0; i < (int)(n); ++i)
#define rep2(i, n) for(int i = 0; i < (int)(n); ++i)
#define rep3(i, a, b) for(int i = (a); i < (int)(b); ++i)
#define rep4(i, a, b, c) for(int i = (a); i < (int)(b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)

#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; --i)
#define ALL(a) (a).begin(), (a).end()
#define Sort(a) (sort((a).begin(), (a).end()))
#define RSort(a) (sort((a).rbegin(), (a).rend()))
#define UNIQUE(a) (a.erase(unique((a).begin(), (a).end()), (a).end()))

typedef long long int ll;
typedef unsigned long long ul;
typedef long double ld;
typedef vector<int> vi;
typedef vector<long long> vll;
typedef vector<char> vc;
typedef vector<string> vst;
typedef vector<double> vd;
typedef vector<long double> vld;
typedef pair<long long, long long> P;

template<class T> long long sum(const T& a){ return accumulate(a.begin(), a.end(), 0LL); }
template<class T> auto min(const T& a){ return *min_element(a.begin(), a.end()); }
template<class T> auto max(const T& a){ return *max_element(a.begin(), a.end()); }

const long long MINF = 0x7fffffffffff;
const long long INF = 0x1fffffffffffffff;
const long long MOD = 998244353;
const long double EPS = 1e-9;
const long double PI = acos(-1);
 
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

template<typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p){ is >> p.first >> p.second; return is; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){ os << "(" << p.first << ", " << p.second << ")"; return os; }
template<typename T> istream &operator>>(istream &is, vector<T> &v){ for(T &in : v) is >> in; return is; }
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, typename S> ostream &operator<<(ostream &os, const map<T, S> &mp){ for(auto &[key, val] : mp){ os << key << ":" << val << " "; } return os; }
template <typename T> ostream &operator<<(ostream &os, const set<T> &st){ auto itr = st.begin(); for(int i = 0; i < (int)st.size(); ++i){ os << *itr << (i + 1 != (int)st.size() ? " " : ""); itr++; } return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &st){ auto itr = st.begin(); for(int i = 0; i < (int)st.size(); ++i){ os << *itr << (i + 1 != (int)st.size() ? " " : ""); itr++; } return os; }
template <typename T> ostream &operator<<(ostream &os, queue<T> q){ while(q.size()){ os << q.front() << " "; q.pop(); } return os; }
template <typename T> ostream &operator<<(ostream &os, deque<T> q){ while(q.size()){ os << q.front() << " "; q.pop_front(); } return os; }
template <typename T> ostream &operator<<(ostream &os, stack<T> st){ while(st.size()){ os << st.top() << " "; st.pop(); } return os; }
template <class T, class Container, class Compare> ostream &operator<<(ostream &os, priority_queue<T, Container, Compare> pq){ while(pq.size()){ os << pq.top() << " "; pq.pop(); } return os; }

template<class T, class U> inline T vin(T& vec, U n) { vec.resize(n); for(int i = 0; i < (int) n; ++i) cin >> vec[i]; return vec; }
template<class T> inline void vout(T vec, string s = "\n"){ for(auto x : vec) cout << x << s; }
template<class... T> void in(T&... a){ (cin >> ... >> a); }
void out(){ cout << '\n'; }
template<class T, class... Ts> void out(const T& a, const Ts&... b){ cout << a; (cout << ... << (cout << ' ', b)); cout << '\n'; }
template<class T, class U> void inGraph(vector<vector<T>>& G, U n, U m, bool directed = false){ G.resize(n); for(int i = 0; i < m; ++i){ int a, b; cin >> a >> b; a--, b--; G[a].push_back(b); if(!directed) G[b].push_back(a); } }

// https://ei1333.github.io/algorithm/namori.html
template< typename G >
struct Namori
{
  const G &g;
  vector< int > in;

  Namori(const G &g) : g(g), in(g.size(), 0) {}

  void decomposition(vector< int > &loop, vector< vector< int > > &forest)
  {
    int N = (int) in.size();
    for(int i = 0; i < N; i++) {
      in[i] = g[i].size();
    }
    forest.resize(N);
    queue< int > que;
    vector< bool > v(N, 0);
    for(int i = 0; i < N; i++) {
      if(in[i] == 1) {
        que.emplace(i);
        v[i] = true;
      }
    }
    while(!que.empty()) {
      int idx = que.front();
      que.pop();
      for(auto &to : g[idx]) {
        if(v[to]) continue;
        --in[to];
        forest[to].push_back(idx);
        forest[idx].push_back(to);
        if(in[to] > 1) continue;
        que.emplace(to);
        v[to] = true;
      }
    }

    function< void(int) > dfs = [&](int idx)
    {
      loop.push_back(idx);
      for(auto &to : g[idx]) {
        if(v[to]) continue;
        v[to] = true;
        dfs(to);
      }
    };
    for(int i = 0; i < N; i++) {
      if(v[i]) continue;
      v[i] = true;
      dfs(i);
      break;
    }
  }
};

namespace modcalc{

    template <typename T>
    T modpow(T x, T n, const T &m){
        T ret = 1 % m;
        x %= m;
        while(n > 0){
            if(n & 1) (ret *= x) %= m;
            (x *= x) %= m;
            n >>= 1;
        }
        return ret;
    }

    template <typename T>
    T modinv(T a, T m){
        T b = m, u = 1, v = 0;
        while(b){
            T t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        u %= m;
        if (u < 0) u += m;
        return u;
    }

    template <typename T>
    T modarithmeticsum(T a, T d, T n, T m){
        T m2 = m * 2;
        a %= m2, n %= m2, d %= m2;
        T b = (n - 1) * d % m2;
        return ((n * (a * 2 + b) % m2) / 2) % m;
    }

    template <typename T>
    T modgeometricsum(T a, T r, T n, T m){
        a %= m;
        if(r == 1){
            n %= m;
            return a * n % m;
        }
        return a * (modpow(r, n, m) + m - 1) % m * modinv(r - 1, m) % m;
    }

    template <typename T>
    T modgeometricsum2(T a, T r, T n, T m){
        a %= m;
        if(r == 1){
            n %= m;
            return a * n % m;
        }
        T ret = 0;
        T x = 1 % m;
        T sum = 0;
        for(int i = 0; n > 0; ++i){
            if(n & 1){
                (ret += x * modpow(r, sum, m) % m) %= m;
                sum |= 1LL << i;
            }
            (x += x * modpow(r, 1LL << i, m) % m) %= m;
            n >>= 1;
        }
        return a * ret % m;
    }
}

template <long long Modulus>
struct ModInt{
    long long val;
    constexpr ModInt(const long long &_val = 0) noexcept : val(_val) {
        normalize();
    }
    void normalize(){
        val = (val % Modulus + Modulus) % Modulus;
    }
    inline ModInt& operator+=(const ModInt& rhs) noexcept {
        if(val += rhs.val, val >= Modulus) val -= Modulus;
        return *this;
    }
    inline ModInt& operator-=(const ModInt& rhs) noexcept {
        if(val -= rhs.val, val < 0) val += Modulus;
        return *this;
    }
    inline ModInt& operator*=(const ModInt& rhs) noexcept {
        val = val * rhs.val % Modulus;
        return *this;
    }
    inline ModInt& operator/=(const ModInt& rhs) noexcept {
        val = val * inv(rhs.val).val % Modulus;
        return *this;
    }
    inline ModInt& operator++() noexcept {
        if(++val >= Modulus) val -= Modulus;
        return *this;
    }
    inline ModInt operator++(int) noexcept {
        ModInt t = val;
        if(++val >= Modulus) val -= Modulus;
        return t;
    }
    inline ModInt& operator--() noexcept {
        if(--val < 0) val += Modulus;
        return *this;
    }
    inline ModInt operator--(int) noexcept {
        ModInt t = val;
        if(--val < 0) val += Modulus;
        return t;
    }
    inline ModInt operator-() const noexcept { return (Modulus - val) % Modulus; }
    inline ModInt inv(void) const { return inv(val); }
    ModInt inv(const long long& n) const {
        long long a = n, b = Modulus, u = 1, v = 0;
        while(b){
            long long t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        u %= Modulus;
        if(u < 0) u += Modulus;
        return u;
    }
    friend inline ModInt operator+(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) += rhs; }
    friend inline ModInt operator-(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) -= rhs; }
    friend inline ModInt operator*(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) *= rhs; }
    friend inline ModInt operator/(const ModInt& lhs, const ModInt& rhs) noexcept { return ModInt(lhs) /= rhs; }
    friend inline bool operator==(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.val == rhs.val; }
    friend inline bool operator!=(const ModInt& lhs, const ModInt& rhs) noexcept { return lhs.val != rhs.val; }
    friend inline istream& operator>>(istream& is, ModInt& x) noexcept {
        is >> x.val;
        x.normalize();
        return is;
    }
    friend inline ostream& operator<<(ostream& os, const ModInt& x) noexcept { return os << x.val; }
};

using mint = ModInt<998244353>;

struct Combination{
    vector<long long> memo, memoinv, inv;
    const long long mod;
    Combination(const int &N, const long long &m) : memo(N + 1), memoinv(N + 1), inv(N + 1), mod(m){
        memo[0] = memo[1] = 1;
        memoinv[0] = memoinv[1] = 1;
        inv[1] = 1;
        for(int i = 2; i <= N; ++i){
            memo[i] = memo[i - 1] * i % mod;
            inv[i] = mod - inv[mod % i] * (m / i) % mod;
            memoinv[i] = memoinv[i - 1] * inv[i] % mod;
        }
    }
    inline long long fact(const long long &n) const {
        return memo[n];
    }
    inline long long factinv(const long long &n) const {
        return memoinv[n];
    }
    inline long long ncr(const long long &n, const long long &r) const {
        if(n < r || r < 0) return 0;
        return (memo[n] * memoinv[r] % mod) * memoinv[n - r] % mod;
    }
    inline long long npr(const long long &n, const long long &r) const {
        if(n < r || r < 0) return 0;
        return (memo[n] % mod) * memoinv[n - r] % mod;
    }
    inline long long nhr(const long long &n, const long long &r) const {
        if(n == 0 && r == 0) return 1;
        return ncr(n + r - 1, r);
    }
};

using namespace modcalc;

ll n, k;

void input(){
    in(n, k);
}

mint dp[200001][2];

void solve(){
    using Graph = vector<vll>;
    Graph G(n);
    rep(i, n){
        ll u, v; in(u, v); u--, v--;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    Namori<Graph> namori(G);
    vi loop;
    vector<vi> forest;

    namori.decomposition(loop, forest);

    ll siz = loop.size();

    dp[0][0] = k;
    rep(i, siz - 2){
        dp[i + 1][1] += dp[i][0] * (k - 1);
        dp[i + 1][1] += dp[i][1] * (k - 2);
        dp[i + 1][0] += dp[i][1];
    }
    mint ans = dp[siz - 2][0] * (k - 1) + dp[siz - 2][1] * (k - 2);
    ans *= modpow(k - 1, n - siz, MOD);
    out(ans);
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(20);
    
    input();
    solve();
}
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