結果

問題 No.1116 Cycles of Dense Graph
ユーザー cn_449cn_449
提出日時 2020-07-18 01:31:01
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
WA  
実行時間 -
コード長 4,193 bytes
コンパイル時間 2,075 ms
コンパイル使用メモリ 144,900 KB
実行使用メモリ 9,544 KB
最終ジャッジ日時 2023-08-20 07:26:46
合計ジャッジ時間 6,143 ms
ジャッジサーバーID
(参考情報)
judge15 / judge11
このコードへのチャレンジ
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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 WA -
testcase_01 WA -
testcase_02 WA -
testcase_03 WA -
testcase_04 WA -
testcase_05 WA -
testcase_06 WA -
testcase_07 WA -
testcase_08 WA -
testcase_09 WA -
testcase_10 WA -
testcase_11 WA -
testcase_12 WA -
testcase_13 WA -
testcase_14 WA -
testcase_15 WA -
testcase_16 WA -
testcase_17 WA -
testcase_18 WA -
testcase_19 WA -
testcase_20 WA -
testcase_21 WA -
testcase_22 WA -
testcase_23 WA -
testcase_24 WA -
testcase_25 WA -
testcase_26 WA -
testcase_27 WA -
testcase_28 WA -
testcase_29 WA -
testcase_30 WA -
testcase_31 AC 12 ms
9,448 KB
testcase_32 WA -
testcase_33 AC 12 ms
9,392 KB
testcase_34 AC 12 ms
9,416 KB
testcase_35 WA -
testcase_36 WA -
testcase_37 WA -
testcase_38 WA -
testcase_39 WA -
testcase_40 WA -
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ソースコード

diff #

//あとでしっかり詰める
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <iomanip>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cassert>
#include <complex>
#include <stdio.h>
#include <time.h>
#include <numeric>
#include <random>
#include <unordered_map>
#include <unordered_set>
#define all(a) a.begin(),a.end()
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define pb push_back
#define debug(x) cerr << #x << ':' << x << '\n'
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> P;
typedef complex<ld> com;
constexpr int inf = 1000000010;
constexpr ll INF = 1000000000000000010;
constexpr ld eps = 1e-12;
constexpr ld pi = 3.141592653589793238;
template<class T, class U> inline bool chmax(T &a, const U &b) { if (a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T &a, const U &b) { if (a > b) { a = b; return true; } return false; }

constexpr ll mod = 1000000007;
vector<ll> fac, inv, facinv;

void modcalc(int modsize) {
	fac.resize(modsize); inv.resize(modsize); facinv.resize(modsize);
	fac[0] = 1; fac[1] = 1; inv[1] = 1;
	facinv[0] = 1; facinv[1] = 1;
	for (ll i = 2; i < modsize; i++) {
		fac[i] = fac[i - 1] * i % mod;
		inv[i] = mod - inv[mod % i] * (mod / i) % mod;
		facinv[i] = facinv[i - 1] * inv[i] % mod;
	}
}

ll modinv(ll a) {
	a %= mod;
	if (a == 0) abort();
	if (a < (ll)inv.size()) return inv[a];
	ll b = mod, u = 1, v = 0;
	while (b) {
		ll t = a / b;
		a -= t * b; swap(a, b);
		u -= t * v; swap(u, v);
	}
	u %= mod;
	if (u < 0) u += mod;
	return u;
}

ll modpow(ll a, ll b) {
	ll ans = 1;
	a %= mod;
	while (b) {
		if (b & 1) ans = ans * a % mod;
		a = a * a % mod;
		b >>= 1;
	}
	return ans;
}

ll modcomb(ll n, ll k) {
	if (n < 0 || k < 0 || n < k) return 0;
	return fac[n] * facinv[k] % mod * facinv[n - k] % mod;
}

ll modperm(ll n, ll k) {
	if (n < 0 || k < 0 || n < k) return 0;
	return fac[n] * facinv[n - k] % mod;
}

ll modhom(ll n, ll k) {
	if (n < 0 || k < 0 || n == 0 && k > 0) return 0;
	if (n == 0 && k == 0) return 1;
	return fac[n + k - 1] * facinv[k] % mod * facinv[n - 1] % mod;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(20);
	modcalc(200010);
	
	vector<ll> sum(200010);
	rep(i, 200005) sum[i + 1] = (sum[i] + fac[i]) % mod;

	int n, m;
	cin >> n >> m;
	vector<ll> a(m), b(m);
	rep(i, m) {
		cin >> a[i] >> b[i];
		a[i]--; b[i]--;
	}
	ll ng = 0;
	for (int i = 1; i < (1 << m); i++) {
		int pcnt = 0;
		rep(j, m) if ((i >> j) & 1) pcnt++;
		map<int, vector<int>> graph;
		map<int, int> deg;
		rep(j, m) {
			if ((i >> j) & 1) {
				deg[a[j]]++; deg[b[j]]++;
				graph[a[j]].pb(b[j]);
				graph[b[j]].pb(a[j]);
			}
		}
		vector<int> use;
		for (auto x : deg) use.pb(x.first);
		map<ll, bool> vis;
		queue<P> que;
		int cycle = 0; int r = 0;
		bool ok = true;
		rep(j, use.size()) {
			int v = use[j];
			if (!vis[v]) {
				r++;
				que.push({ v,-1 });
				while (!que.empty()) {
					P p = que.front(); que.pop();
					int nowv = p.first; int prev = p.second;
					vis[nowv] = true;
					int cnt = 0;
					for (int nxtv : graph[nowv]) {
						if (nxtv == prev) continue;
						cnt++;
						if (vis[nxtv] && nxtv != v) ok = false;
						if (nxtv == v) cycle++;
						if (!vis[nxtv]) {
							que.push({ nxtv,nowv });
						}
					}
					if (cnt > 1) ok = false;
				}
			}
		}
		if (i == 1) debug(cycle), debug(r);
		if (cycle > 1) ok = false;
		if (cycle == 1 && r > 1) ok = false;
		ll res = 0;
		if (ok) {
			if (cycle == 1 && r == 1) res = 1;
			else {
				res = modpow(2, r - 1) * (sum[n - use.size() + r] - sum[r - 1] + mod) % mod;
			}
		}
		if (pcnt & 1) ng += res;
		else ng -= res;
	}
	ng %= mod;
	if (ng < 0) ng += mod;
	ll ans = 0;
	for (int i = 3; i <= n; i++) {
		ll c = fac[n] * facinv[n - i] % mod;
		c *= modinv(2); c %= mod;
		c *= modinv(i); c %= mod;
		ans += c;
	}
	ans -= ng;
	ans %= mod;
	if (ans < 0) ans += mod;
	cout << ans << '\n';
}
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