結果

問題 No.2531 Coloring Vertices on Namori
コンテスト
ユーザー siro53
提出日時 2023-11-04 17:20:07
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 160 ms / 2,000 ms
コード長 5,692 bytes
コンパイル時間 2,264 ms
コンパイル使用メモリ 208,360 KB
最終ジャッジ日時 2025-02-17 19:15:00
ジャッジサーバーID
（参考情報） 		judge5 / 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 * 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 # 

#line 1 "combined.cpp"
#pragma region Macros
#include <bits/stdc++.h>
using namespace std;
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;
}
#ifdef DEBUG
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
    os << '{';
    for(int i = 0; i < (int)v.size(); i++) {
        if(i) { os << ','; }
        os << v[i];
    }
    os << '}';
    return os;
}
void debugg() { cerr << endl; }
template <class T, class... Args>
void debugg(const T &x, const Args &... args) {
    cerr << " " << x;
    debugg(args...);
}
#define debug(...)                                                             \
    cerr << __LINE__ << " [" << #__VA_ARGS__ << "]: ", debugg(__VA_ARGS__)
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif

struct Setup {
    Setup() {
        cin.tie(0);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(15);
    }
} __Setup;

using ll = long long;
#define OVERLOAD3(_1, _2, _3, name, ...) name
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define REP1(i, n) for(int i = 0; i < int(n); i++)
#define REP2(i, a, b) for(int i = (a); i < int(b); i++)
#define REP(...) OVERLOAD3(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
#define UNIQUE(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define REVERSE(v) reverse(ALL(v))
#define SZ(v) ((int)(v).size())
const int INF = 1 << 30;
const ll LLINF = 1LL << 60;
constexpr int MOD = 1000000007;
constexpr int MOD2 = 998244353;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, -1, 0, 1};

void Case(int i) { cout << "Case #" << i << ": "; }
int popcount(int x) { return __builtin_popcount(x); }
ll popcount(ll x) { return __builtin_popcountll(x); }
#pragma endregion Macros

#line 2 "/Users/siro53/kyo-pro/compro_library/modint/modint.hpp"

#line 6 "/Users/siro53/kyo-pro/compro_library/modint/modint.hpp"

template <int mod> class ModInt {
  public:
    ModInt() : x(0) {}
    ModInt(long long y)
        : x(y >= 0 ? y % umod() : (umod() - (-y) % umod()) % umod()) {}
    unsigned int val() const { return x; }
    ModInt &operator+=(const ModInt &p) {
        if((x += p.x) >= umod()) x -= umod();
        return *this;
    }
    ModInt &operator-=(const ModInt &p) {
        if((x += umod() - p.x) >= umod()) x -= umod();
        return *this;
    }
    ModInt &operator*=(const ModInt &p) {
        x = (unsigned int)(1ULL * x * p.x % umod());
        return *this;
    }
    ModInt &operator/=(const ModInt &p) {
        *this *= p.inv();
        return *this;
    }
    ModInt operator-() const { return ModInt(-(long long)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 inv() const {
        long long a = x, b = mod, u = 1, v = 0, t;
        while(b > 0) {
            t = a / b;
            std::swap(a -= t * b, b);
            std::swap(u -= t * v, v);
        }
        return ModInt(u);
    }
    ModInt pow(unsigned long long n) const {
        ModInt ret(1), mul(x);
        while(n > 0) {
            if(n & 1) ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }
    friend std::ostream &operator<<(std::ostream &os, const ModInt &p) {
        return os << p.x;
    }
    friend std::istream &operator>>(std::istream &is, ModInt &a) {
        long long t;
        is >> t;
        a = ModInt<mod>(t);
        return (is);
    }
    static constexpr int get_mod() { return mod; }

  private:
    unsigned int x;
    static constexpr unsigned int umod() { return mod; }
};
#line 78 "combined.cpp"
using mint = ModInt<MOD2>;

mint calc(int N, int K) {
    // dp[i][j] = i番目の頂点まで色を決めて、0番目と色が同じ(j=1)、違う(j=0)
    vector dp(N, vector<mint>(2, 0));
    dp[0][1] = K;
    REP(i, N - 1) {
        // 0 -> 0
        dp[i+1][0] += dp[i][0] * (K - 2);
        // 0 -> 1
        dp[i+1][1] += dp[i][0];
        // 1 -> 0
        dp[i+1][0] += dp[i][1] * (K - 1);
    }
    return dp[N-1][0];
}

void solve() {
    int N, K;
    cin >> N >> K;
    vector<vector<int>> G(N);
    vector<int> deg(N);
    REP(_, N) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        G[a].push_back(b);
        G[b].push_back(a);
        deg[a]++;
        deg[b]++;
    }
    queue<int> que;
    vector<bool> seen(N, false);
    REP(i, N) if(deg[i] == 1) {
        que.push(i);
        seen[i] = true;
    }
    while(!que.empty()) {
        int u = que.front();
        que.pop();
        for(int v : G[u]) {
            if(seen[v]) continue;
            deg[v]--;
            if(deg[v] == 1) {
                que.push(v);
                seen[v] = true;
            }
        }
    }
    int loop_size = 0;
    REP(i, N) if(!seen[i]) loop_size++;
    debug(loop_size);
    mint ans = calc(loop_size, K) * mint(K - 1).pow(N - loop_size);
    cout << ans << endl;
}

int main() {
    int T{1};
    // cin >> T;
    while(T--) solve();
}
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