結果

問題 No.3346 Tree to DAG
コンテスト
ユーザー KumaTachiRen
提出日時 2025-11-13 23:57:46
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 137 ms / 2,000 ms
コード長 11,424 bytes
コンパイル時間 4,141 ms
コンパイル使用メモリ 297,696 KB
実行使用メモリ 24,192 KB
最終ジャッジ日時 2025-11-13 23:57:55
合計ジャッジ時間 7,186 ms
ジャッジサーバーID
（参考情報） 		judge4 / 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 * 2
other AC * 39
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 2 "library/template/template.hpp"
#include <bits/stdc++.h>
using namespace std;

#line 2 "library/template/macro.hpp"
#define rep(i, a, b) for (int i = (a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (int)(b) - 1; i >= (a); i--)
#define ALL(v) (v).begin(), (v).end()
#define UNIQUE(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define SZ(v) (int)v.size()
#define MIN(v) *min_element(ALL(v))
#define MAX(v) *max_element(ALL(v))
#define LB(v, x) int(lower_bound(ALL(v), (x)) - (v).begin())
#define UB(v, x) int(upper_bound(ALL(v), (x)) - (v).begin())
#define YN(b) cout << ((b) ? "YES" : "NO") << "\n";
#define Yn(b) cout << ((b) ? "Yes" : "No") << "\n";
#define yn(b) cout << ((b) ? "yes" : "no") << "\n";
#line 6 "library/template/template.hpp"

#line 2 "library/template/util.hpp"
using uint = unsigned int;
using ll = long long int;
using ull = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;

template <class T, class S = T>
S SUM(const vector<T>& a) {
  return accumulate(ALL(a), S(0));
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

template <class T>
int popcnt(T x) {
  return __builtin_popcountll(x);
}
template <class T>
int topbit(T x) {
  return (x == 0 ? -1 : 63 - __builtin_clzll(x));
}
template <class T>
int lowbit(T x) {
  return (x == 0 ? -1 : __builtin_ctzll(x));
}
#line 8 "library/template/template.hpp"

#line 2 "library/template/inout.hpp"
struct Fast {
  Fast() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(15);
  }
} fast;

template <class T1, class T2>
istream& operator>>(istream& is, pair<T1, T2>& p) {
  return is >> p.first >> p.second;
}
template <class T1, class T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
  return os << p.first << " " << p.second;
}
template <class T>
istream& operator>>(istream& is, vector<T>& a) {
  for (auto& v : a) is >> v;
  return is;
}
template <class T>
ostream& operator<<(ostream& os, const vector<T>& a) {
  for (auto it = a.begin(); it != a.end();) {
    os << *it;
    if (++it != a.end()) os << " ";
  }
  return os;
}
template <class T>
ostream& operator<<(ostream& os, const set<T>& st) {
  os << "{";
  for (auto it = st.begin(); it != st.end();) {
    os << *it;
    if (++it != st.end()) os << ",";
  }
  os << "}";
  return os;
}
template <class T1, class T2>
ostream& operator<<(ostream& os, const map<T1, T2>& mp) {
  os << "{";
  for (auto it = mp.begin(); it != mp.end();) {
    os << it->first << ":" << it->second;
    if (++it != mp.end()) os << ",";
  }
  os << "}";
  return os;
}

void in() {}
template <typename T, class... U>
void in(T& t, U&... u) {
  cin >> t;
  in(u...);
}
void out() { cout << "\n"; }
template <typename T, class... U, char sep = ' '>
void out(const T& t, const U&... u) {
  cout << t;
  if (sizeof...(u)) cout << sep;
  out(u...);
}
#line 10 "library/template/template.hpp"

#line 2 "library/template/debug.hpp"
#ifdef LOCAL
#define debug 1
#define show(...) _show(0, #__VA_ARGS__, __VA_ARGS__)
#else
#define debug 0
#define show(...) true
#endif
template <class T>
void _show(int i, T name) {
  cerr << '\n';
}
template <class T1, class T2, class... T3>
void _show(int i, const T1& a, const T2& b, const T3&... c) {
  for (; a[i] != ',' && a[i] != '\0'; i++) cerr << a[i];
  cerr << ":" << b << " ";
  _show(i + 1, a, c...);
}
#line 2 "library/math/util.hpp"

namespace Math {
template <class T>
T safe_mod(T a, T b) {
  assert(b != 0);
  if (b < 0) a = -a, b = -b;
  a %= b;
  return a >= 0 ? a : a + b;
}
template <class T>
T floor(T a, T b) {
  assert(b != 0);
  if (b < 0) a = -a, b = -b;
  return a >= 0 ? a / b : (a + 1) / b - 1;
}
template <class T>
T ceil(T a, T b) {
  assert(b != 0);
  if (b < 0) a = -a, b = -b;
  return a > 0 ? (a - 1) / b + 1 : a / b;
}
long long isqrt(long long n) {
  if (n <= 0) return 0;
  long long x = sqrt(n);
  while ((x + 1) * (x + 1) <= n) x++;
  while (x * x > n) x--;
  return x;
}
// return g=gcd(a,b)
// a*x+b*y=g
// - b!=0 -> 0<=x<|b|/g
// - b=0  -> ax=g
template <class T>
T ext_gcd(T a, T b, T& x, T& y) {
  T a0 = a, b0 = b;
  bool sgn_a = a < 0, sgn_b = b < 0;
  if (sgn_a) a = -a;
  if (sgn_b) b = -b;
  if (b == 0) {
    x = sgn_a ? -1 : 1;
    y = 0;
    return a;
  }
  T x00 = 1, x01 = 0, x10 = 0, x11 = 1;
  while (b != 0) {
    T q = a / b, r = a - b * q;
    x00 -= q * x01;
    x10 -= q * x11;
    swap(x00, x01);
    swap(x10, x11);
    a = b, b = r;
  }
  x = x00, y = x10;
  if (sgn_a) x = -x;
  if (sgn_b) y = -y;
  if (b0 != 0) {
    a0 /= a, b0 /= a;
    if (b0 < 0) a0 = -a0, b0 = -b0;
    T q = x >= 0 ? x / b0 : (x + 1) / b0 - 1;
    x -= b0 * q;
    y += a0 * q;
  }
  return a;
}
constexpr long long inv_mod(long long x, long long m) {
  x %= m;
  if (x < 0) x += m;
  long long a = m, b = x;
  long long y0 = 0, y1 = 1;
  while (b > 0) {
    long long q = a / b;
    swap(a -= q * b, b);
    swap(y0 -= q * y1, y1);
  }
  if (y0 < 0) y0 += m / a;
  return y0;
}
long long pow_mod(long long x, long long n, long long m) {
  x = (x % m + m) % m;
  long long y = 1;
  while (n) {
    if (n & 1) y = y * x % m;
    x = x * x % m;
    n >>= 1;
  }
  return y;
}
constexpr long long pow_mod_constexpr(long long x, long long n, int m) {
  if (m == 1) return 0;
  unsigned int _m = (unsigned int)(m);
  unsigned long long r = 1;
  unsigned long long y = x % m;
  if (y >= m) y += m;
  while (n) {
    if (n & 1) r = (r * y) % _m;
    y = (y * y) % _m;
    n >>= 1;
  }
  return r;
}
constexpr bool is_prime_constexpr(int n) {
  if (n <= 1) return false;
  if (n == 2 || n == 7 || n == 61) return true;
  if (n % 2 == 0) return false;
  long long d = n - 1;
  while (d % 2 == 0) d /= 2;
  constexpr long long bases[3] = {2, 7, 61};
  for (long long a : bases) {
    long long t = d;
    long long y = pow_mod_constexpr(a, t, n);
    while (t != n - 1 && y != 1 && y != n - 1) {
      y = y * y % n;
      t <<= 1;
    }
    if (y != n - 1 && t % 2 == 0) {
      return false;
    }
  }
  return true;
}
template <int n>
constexpr bool is_prime = is_prime_constexpr(n);
};  // namespace Math
#line 3 "library/modint/modint.hpp"

template <unsigned int m = 998244353>
struct ModInt {
  using mint = ModInt;
  static constexpr unsigned int get_mod() { return m; }
  static mint raw(int v) {
    mint x;
    x._v = v;
    return x;
  }
  ModInt() : _v(0) {}
  ModInt(int64_t v) {
    long long x = (long long)(v % (long long)(umod()));
    if (x < 0) x += umod();
    _v = (unsigned int)(x);
  }
  unsigned int val() const { return _v; }
  mint& operator++() {
    _v++;
    if (_v == umod()) _v = 0;
    return *this;
  }
  mint& operator--() {
    if (_v == 0) _v = umod();
    _v--;
    return *this;
  }
  mint operator++(int) {
    mint result = *this;
    ++*this;
    return result;
  }
  mint operator--(int) {
    mint result = *this;
    --*this;
    return result;
  }
  mint& operator+=(const mint& rhs) {
    _v += rhs._v;
    if (_v >= umod()) _v -= umod();
    return *this;
  }
  mint& operator-=(const mint& rhs) {
    _v -= rhs._v;
    if (_v >= umod()) _v += umod();
    return *this;
  }
  mint& operator*=(const mint& rhs) {
    unsigned long long z = _v;
    z *= rhs._v;
    _v = (unsigned int)(z % umod());
    return *this;
  }
  mint& operator/=(const mint& rhs) { return *this *= rhs.inv(); }
  mint operator+() const { return *this; }
  mint operator-() const { return mint() - *this; }
  mint pow(long long n) const {
    assert(0 <= n);
    mint x = *this, r = 1;
    while (n) {
      if (n & 1) r *= x;
      x *= x;
      n >>= 1;
    }
    return r;
  }
  mint inv() const {
    if (is_prime) {
      assert(_v);
      return pow(umod() - 2);
    } else {
      auto inv = Math::inv_mod(_v, umod());
      return raw(inv);
    }
  }
  friend mint operator+(const mint& lhs, const mint& rhs) { return mint(lhs) += rhs; }
  friend mint operator-(const mint& lhs, const mint& rhs) { return mint(lhs) -= rhs; }
  friend mint operator*(const mint& lhs, const mint& rhs) { return mint(lhs) *= rhs; }
  friend mint operator/(const mint& lhs, const mint& rhs) { return mint(lhs) /= rhs; }
  friend bool operator==(const mint& lhs, const mint& rhs) { return lhs._v == rhs._v; }
  friend bool operator!=(const mint& lhs, const mint& rhs) { return lhs._v != rhs._v; }
  friend istream& operator>>(istream& is, mint& x) {
    int64_t v;
    is >> v;
    x = mint(v);
    return is;
  }
  friend ostream& operator<<(ostream& os, const mint& x) { return os << x.val(); }

 private:
  unsigned int _v;
  static constexpr unsigned int umod() { return m; }
  static constexpr bool is_prime = Math::is_prime<m>;
};
#line 3 "main.cpp"
using mint = ModInt<998244353>;

void solve() {
  int n;
  in(n);

  vector<vector<int>> g(n);
  rep(i, 0, n - 1) {
    int u, v;
    in(u, v);
    g[u - 1].push_back(v - 1);
    g[v - 1].push_back(u - 1);
  }

  vector<int> dp(n);
  auto dfs1 = [&](auto rec, int x, int p) -> void {
    for (auto y : g[x]) {
      if (y == p) continue;
      rec(rec, y, x);
      chmax(dp[x], dp[y] + 1);
    }
  };
  dfs1(dfs1, 0, -1);

  using ar = array<int, 3>;
  ar ma{0, 0, 0};

  priority_queue<int> pq;
  auto normalize = [&](vector<int> a) -> vector<int> {
    sort(ALL(a));
    for (auto v : a) pq.push(-v);
    vector<int> b;
    while (!pq.empty()) {
      int v = -pq.top();
      pq.pop();
      if (!pq.empty() && -pq.top() == v) {
        pq.pop();
        pq.push(-(v + 1));
      } else {
        b.push_back(v);
      }
    }
    return b;
  };

  auto comp = [&](ar a, ar b) -> bool {
    // f(a)=2^(1-a[0]-a[1])+2^(1-a[1]-a[2])+2^(1-a[0]-a[2])-3*2^(-a[0]-a[1]-a[2])
    // f(a)>f(b) ?

    vector<int> x, y;
    x.push_back(1 - a[0] - a[1]);
    x.push_back(1 - a[0] - a[2]);
    x.push_back(1 - a[1] - a[2]);
    rep(i, 0, 3) x.push_back(-b[0] - b[1] - b[2]);
    y.push_back(1 - b[0] - b[1]);
    y.push_back(1 - b[0] - b[2]);
    y.push_back(1 - b[1] - b[2]);
    rep(i, 0, 3) y.push_back(-a[0] - a[1] - a[2]);

    x = normalize(x);
    y = normalize(y);
    while (true) {
      if (x.empty()) return false;
      if (y.empty()) return true;
      if (x.back() != y.back()) return x.back() > y.back();
      x.pop_back();
      y.pop_back();
    }
  };

  auto dfs2 = [&](auto rec, int x, int p, int v) -> void {
    int sz = int(g[x].size()) - (p != -1);
    rep(i, 0, sz) {
      if (g[x][i] == p) {
        swap(g[x].back(), g[x][i]);
        break;
      }
    }

    vector<int> a(sz);
    rep(i, 0, sz) a[i] = dp[g[x][i]] + 1;
    if (p != -1) a.push_back(v);
    if (a.size() == 2) a.push_back(0);
    if (a.size() >= 3) {
      sort(ALL(a));
      reverse(ALL(a));
      array<int, 3> b{a[2], a[1], a[0]};
      if (comp(ma, b)) ma = b;
    }

    vector<int> suf(sz + 1);
    rrep(i, 0, sz) suf[i] = max(dp[g[x][i]] + 1, suf[i + 1]);
    int pre = v;
    rep(i, 0, sz) {
      rec(rec, g[x][i], x, max(pre, suf[i + 1]) + 1);
      chmax(pre, dp[g[x][i]] + 1);
    }
  };
  dfs2(dfs2, 0, -1, 0);

  mint m2 = 2;
  mint ans = m2.pow(n + 2);
  ans -= m2.pow(n + 1 - ma[0] - ma[1]);
  ans -= m2.pow(n + 1 - ma[0] - ma[2]);
  ans -= m2.pow(n + 1 - ma[1] - ma[2]);
  ans += 3 * m2.pow(n - ma[0] - ma[1] - ma[2]);
  out(ans);
}

int main() {
  int t = 1;
  // in(t);
  while (t--) solve();
}
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