結果
| 問題 |
No.827 総神童数
|
| コンテスト | |
| ユーザー |
 mdj982
|
| 提出日時 | 2019-05-03 21:54:12 |
| 言語 | C++14 (gcc 13.3.0 + boost 1.87.0) |
| 結果 |
AC
|
| 実行時間 | 267 ms / 2,000 ms |
| コード長 | 6,618 bytes |
| コンパイル時間 | 2,195 ms |
| コンパイル使用メモリ | 188,228 KB |
| 実行使用メモリ | 26,344 KB |
| 最終ジャッジ日時 | 2024-12-31 17:52:35 |
| 合計ジャッジ時間 | 8,111 ms |
|
ジャッジサーバーID （参考情報） |
judge4 / judge1 |
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| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 36 |
ソースコード
#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>;
using ll = long long int;
using vll = vector<ll>; using vvll = vector<vll>; using vvvll = vector<vvll>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using cdouble = complex<double>;
const double eps = 1e-9;
const double INFD = numeric_limits<double>::infinity();
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loopll(i, n) for(ll i = 0; i < (ll)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopll1(i, n) for(ll i = 1; i <= (ll)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Looprll(i, n) for(ll i = (ll)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
#define Looprll1(i, n) for(ll i = (ll)n; i >= 1; i--)
#define Foreach(buf, container) for(auto buf : container)
#define Loopdiag(i, j, h, w, sum) for(int i = ((sum) >= (h) ? (h) - 1 : (sum)), j = (sum) - i; i >= 0 && j < (w); i--, j++)
#define Loopdiagr(i, j, h, w, sum) for(int j = ((sum) >= (w) ? (w) - 1 : (sum)), i = (sum) - j; j >= 0 && i < (h); j--, i++)
#define Loopdiagsym(i, j, h, w, gap) for (int i = ((gap) >= 0 ? (gap) : 0), j = i - (gap); i < (h) && j < (w); i++, j++)
#define Loopdiagsymr(i, j, h, w, gap) for (int i = ((gap) > (h) - (w) - 1 ? (h) - 1 : (w) - 1 + (gap)), j = i - (gap); i >= 0 && j >= 0; i--, j--)
#define Loopitr(itr, container) for(auto itr = container.begin(); itr != container.end(); itr++)
#define printv(vector) Loop(ex_i, vector.size()) { cout << vector[ex_i] << " "; } cout << endl;
#define printmx(matrix) Loop(ex_i, matrix.size()) { Loop(ex_j, matrix[ex_i].size()) { cout << matrix[ex_i][ex_j] << " "; } cout << endl; }
#define quickio() ios::sync_with_stdio(false); cin.tie(0);
#define bitmanip(m,val) static_cast<bitset<(int)m>>(val)
#define Comp(type_t) bool operator<(const type_t &another) const
#define fst first
#define snd second
bool nearlyeq(double x, double y) { return abs(x - y) < eps; }
bool inrange(ll x, ll t) { return x >= 0 && x < t; }
bool inrange(vll xs, ll t) { Foreach(x, xs) if (!(x >= 0 && x < t)) return false; return true; }
int ceillog2(ll x) { int ret = 0; x--; while (x > 0) { ret++; x >>= 1; } return ret; }
ll rndf(double x) { return (ll)(x + (x >= 0 ? 0.5 : -0.5)); }
ll floorsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (m * m <= x ? 0 : -1); }
ll ceilsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (x <= m * m ? 0 : 1); }
ll rnddiv(ll a, ll b) { return (a / b + (a % b * 2 >= b ? 1 : 0)); }
ll ceildiv(ll a, ll b) { return (a / b + (a % b == 0 ? 0 : 1)); }
ll gcd(ll m, ll n) { if (n == 0) return m; else return gcd(n, m % n); }
ll lcm(ll m, ll n) { return m * n / gcd(m, n); }
/*******************************************************/
int n;
vvi lst;
vi cnt;
vi from;
void count(int a, int c) {
cnt[a] = c;
Foreach(b, lst[a]) {
if (from[b] == INT_MIN) {
from[b] = a;
count(b, c + 1);
}
}
}
namespace mod_op {
const ll MOD = (ll)1e9 + 7;
class modll {
private:
ll val;
ll modify(ll x) { ll ret = x % MOD; if (ret < 0) ret += MOD; return ret; }
ll inv(ll x) {
if (x == 0) return 1 / x;
else if (x == 1) return 1;
else return modify(inv(MOD % x) * modify(-MOD / x));
}
public:
modll(ll init = 0) { val = modify(init); return; }
modll(const modll& another) { val = another.val; return; }
modll& operator=(const modll &another) { val = another.val; return *this; }
modll operator+(const modll &x) { return modify(val + x.val); }
modll operator-(const modll &x) { return modify(val - x.val); }
modll operator*(const modll &x) { return modify(val * x.val); }
modll operator/(const modll &x) { return modify(val * inv(x.val)); }
modll& operator+=(const modll &x) { val = modify(val + x.val); return *this; }
modll& operator-=(const modll &x) { val = modify(val - x.val); return *this; }
modll& operator*=(const modll &x) { val = modify(val * x.val); return *this; }
modll& operator/=(const modll &x) { val = modify(val * inv(x.val)); return *this; }
bool operator==(const modll &x) { return val == x.val; }
bool operator!=(const modll &x) { return val != x.val; }
friend istream& operator >> (istream &is, modll& x) { is >> x.val; return is; }
friend ostream& operator << (ostream &os, const modll& x) { os << x.val; return os; }
ll get_val() { return val; }
};
modll pow(modll n, ll p) {
modll ret;
if (p == 0) ret = 1;
else if (p == 1) ret = n;
else {
ret = pow(n, p / 2);
ret *= ret;
if (p % 2 == 1) ret *= n;
}
return ret;
}
vector<modll> facts;
void make_facts(int n) {
if (facts.empty()) facts.push_back(modll(1));
for (int i = (int)facts.size(); i <= n; ++i) facts.push_back(modll(facts.back() * (ll)i));
return;
}
vector<modll> ifacts;
vector<modll> invs;
void make_invs(int n) {
if (invs.empty()) {
invs.push_back(modll(0));
invs.push_back(modll(1));
}
for (int i = (int)invs.size(); i <= n; ++i) {
// because 0 = MOD = kq + r, 1/k = -q/r
invs.push_back(invs[(int)MOD % i] * ((int)MOD - (int)MOD / i));
}
return;
}
void make_ifacts(int n) {
make_invs(n);
if (ifacts.empty()) ifacts.push_back(modll(1));
for (int i = (int)ifacts.size(); i <= n; ++i) ifacts.push_back(modll(ifacts.back() * invs[i]));
return;
}
//nCr
modll combination(ll n, ll r) {
if (n >= r && r >= 0) {
modll ret;
make_facts((int)n);
make_ifacts((int)n);
ret = facts[(unsigned)n] * ifacts[(unsigned)r] * ifacts[(unsigned)(n - r)];
return ret;
}
else return 0;
}
modll get_fact(ll n) {
make_facts((int)n);
return facts[(int)n];
}
modll get_ifact(ll n) {
make_ifacts((int)n);
return ifacts[(int)n];
}
//log_a(b), if x does not exist, return -1
ll disc_log(modll a, modll b) {
ll ret = -1;
ll m = ceilsqrt(MOD);
unordered_map<ll, ll> mp;
modll x = 1;
Loop(i, m) {
mp[x.get_val()] = i;
x *= a;
}
x = modll(1) / pow(a, m);
modll k = b;
Loop(i, m) {
if (mp.find(k.get_val()) == mp.end()) k *= x;
else {
ret = i * m + mp[k.get_val()];
break;
}
}
return ret;
}
}
using namespace mod_op;
using vmodll = vector<modll>;
using vvmodll = vector<vmodll>;
using vvvmodll = vector<vvmodll>;
int main() {
cin >> n;
lst.resize(n);
cnt.resize(n);
from = vi(n, INT_MIN);
Loop(i, n - 1) {
int s, t; cin >> s >> t; s--; t--;
lst[s].push_back(t);
lst[t].push_back(s);
}
from[0] = -1;
count(0, 1);
//
modll ans = 0;
Loop(i, n) {
ans += get_fact(n) / cnt[i];
}
cout << ans << endl;
}