結果

問題 No.827 総神童数
ユーザー fumiphysfumiphys
提出日時 2019-05-12 13:19:07
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 165 ms / 2,000 ms
コード長 5,344 bytes
コンパイル時間 1,623 ms
コンパイル使用メモリ 170,860 KB
実行使用メモリ 23,556 KB
最終ジャッジ日時 2023-09-17 03:45:02
合計ジャッジ時間 6,177 ms
ジャッジサーバーID
（参考情報） 		judge11 / judge13
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 4 ms
8,032 KB
testcase_01 AC 5 ms
8,044 KB
testcase_02 AC 4 ms
8,044 KB
testcase_03 AC 4 ms
8,040 KB
testcase_04 AC 4 ms
8,084 KB
testcase_05 AC 5 ms
8,056 KB
testcase_06 AC 4 ms
8,060 KB
testcase_07 AC 4 ms
8,032 KB
testcase_08 AC 4 ms
8,264 KB
testcase_09 AC 160 ms
23,556 KB
testcase_10 AC 50 ms
12,940 KB
testcase_11 AC 6 ms
8,364 KB
testcase_12 AC 24 ms
10,312 KB
testcase_13 AC 124 ms
20,992 KB
testcase_14 AC 8 ms
8,572 KB
testcase_15 AC 47 ms
12,868 KB
testcase_16 AC 120 ms
18,828 KB
testcase_17 AC 149 ms
20,992 KB
testcase_18 AC 62 ms
14,316 KB
testcase_19 AC 165 ms
18,024 KB
testcase_20 AC 110 ms
15,212 KB
testcase_21 AC 71 ms
13,148 KB
testcase_22 AC 119 ms
15,672 KB
testcase_23 AC 5 ms
8,176 KB
testcase_24 AC 140 ms
16,848 KB
testcase_25 AC 98 ms
14,888 KB
testcase_26 AC 142 ms
16,796 KB
testcase_27 AC 80 ms
13,676 KB
testcase_28 AC 80 ms
13,604 KB
testcase_29 AC 60 ms
12,620 KB
testcase_30 AC 19 ms
9,264 KB
testcase_31 AC 48 ms
11,772 KB
testcase_32 AC 46 ms
11,288 KB
testcase_33 AC 162 ms
17,564 KB
testcase_34 AC 144 ms
16,836 KB
testcase_35 AC 49 ms
11,616 KB
testcase_36 AC 73 ms
13,140 KB
testcase_37 AC 96 ms
14,384 KB
testcase_38 AC 155 ms
17,240 KB
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 # 

// includes
#include <bits/stdc++.h>

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define vrep(v, i) for(int i = 0; i < (v).size(); i++)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
#define dump(a, n) for(int i = 0; i < n; i++)cout << a[i] << "\n "[i + 1 != n];
#define dump2(a, n, m) for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)cout << a[i][j] << "\n "[j + 1 != m];
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
typedef complex<double> cd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << p.first << " " << p.second; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}

template <typename T>
T power(T a, T n, T mod) {
  T res = 1;
  T tmp = n;
  T curr = a;
  while(tmp){
    if(tmp % 2 == 1){
      res = (T)((ll)res * curr % mod);
    }
    curr = (T)((ll)curr * curr % mod);
    tmp >>= 1;
  }
  return res;
}

struct Factorial{
  int n;
  const int MOD = 1e9 + 7;
  vector<long long> fac;
  vector<long long> inv_;
  Factorial(int n): n(n){
    fac.resize(n + 1);
    inv_.resize(n + 1);
    calc_factorial();
    calc_inv();
  }
  void calc_factorial(){
    fac[0] = 1;
    for(int i = 1; i <= n; i++){
      fac[i] = i * fac[i-1] % MOD;
    }
  }
  void calc_inv(){
    inv_[n] = power<long long>(fac[n], MOD - 2, MOD);
    for(int i = n - 1; i >= 0; i--){
      inv_[i] = (i + 1) * inv_[i+1] % MOD;
    }
  }
  long long& operator[](size_t i){
    if(i < 0 || i > n){
      cerr << "list index out of range" << endl;
      abort();
    }
    return fac[i];
  }
  long long inv(size_t i){
    if(i < 0 || i > n){
      cerr << "list index out of range" << endl;
      abort();
    }
    return inv_[i];
  }
  long long comb(int n, int k){
    if(n < k)return 0;
    long long res = fac[n];
    res = res * inv_[n-k] % MOD;
    res = res * inv_[k] % MOD;
    return res;
  }
  long long perm(int n, int k){
    if(n < k)return 0;
    long long res = fac[n];
    res = res * inv_[n-k] % MOD;
    return res;
  }
  long long h(int n, int k){
    if(n == 0 && k == 0)return 1;
    return comb(n + k - 1, k);
  }
};

vector<int> edge[200001];
bool vis[200001];
int h[200001];

void dfs(int i){
  vis[i] = true;
  for(auto e: edge[i]){
    if(!vis[e]){
      h[e] = h[i] + 1;
      dfs(e);
    }
  }
}

template<typename T>
T extgcd(T a, T b, T &x, T &y){
  T d = a;
  if(b != 0){
    d = extgcd(b, a % b, y, x);
    y -= (a / b) * x;
  }else{
    x = 1, y = 0;
  }
  return d;
}

template <typename T>
T modinv(T a, T m){
  long long x = 0, y = 0;
  extgcd<long long>(a, m, x, y);
  x %= m;
  if(x < 0)x += m;
  return x;
}

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  rep(i, n - 1){
    int u, v;
    cin >> u >> v, u--, v--;
    edge[u].pb(v);
    edge[v].pb(u);
  }
  dfs(0);
  Factorial fac(n);
  ll res = 0;
  rep(i, n){
    ll tmp = modinv(h[i] + 1, mod);
    res = (res + tmp) % mod;
  }
  cout << res * fac.fac[n] % mod << endl;
  return 0;
}
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