Submission #1127260

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127260		TrieTr	Amusement Park (CEOI19_amusementpark)	C++20	19 / 100	3 ms	328 KiB

amusementpark

#include<bits/stdc++.h>
using namespace std;

void local() {
	#define taskname ""
	if(fopen(taskname".inp", "r")) {
		freopen(taskname".inp", "r", stdin);
		freopen(taskname".out", "w", stdout);
	}
}

#define ll long long
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

template <class X, class Y> bool mini(X& x, Y y) {return x > y ? x = y, true : false;}
template <class X, class Y> bool maxi(X& x, Y y) {return x < y ? x = y, true : false;}

const int N = 18 + 5;
const int mod = 998244353;
void add(int& x, int y) {
	if((x += y) >= mod) x -= mod;
}

int n, m;
vector<pair<int, int>> edge;

namespace sub2 {
	bool check() {
		return n <= 6;
	}
	vector<int> adj[N];
	int inDeg[N], res = 0;
	void dq(int i, int cost = 0) {
		if(i == m) {
			memset(inDeg, 0, sizeof(inDeg));
			for(int u = 1; u <= n; u++) {
				for(int& v : adj[u]) {
					inDeg[v]++;
				}
			}
			queue<int> q;
			for(int u = 1; u <= n; u++) if(inDeg[u] == 0) q.emplace(u);
			int cnt = 0;
			while(!q.empty()) {
				int u = q.front(); q.pop(); cnt++;
				for(int& v : adj[u]) {
					inDeg[v]--;
					if(inDeg[v] == 0) q.emplace(v);
				}
			}
			if(cnt == n) add(res, cost);
			return;
		}
		int u, v; tie(u, v) = edge[i];
		adj[u].emplace_back(v); dq(i + 1, cost); adj[u].pop_back();
		adj[v].emplace_back(u); dq(i + 1, cost + 1); adj[v].pop_back();
	}
	void solve() {
		dq(0);
		cout << res;
	}
}

int main() {
	fastio; local();
	cin >> n >> m;
	for(int i = 1; i <= m; i++) {
		int u, v; cin >> u >> v;
		edge.emplace_back(u, v);
	}
	if(sub2::check()) sub2::solve();
}

Compilation message (stderr)

amusementpark.cpp: In function 'void local()':
amusementpark.cpp:7:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
amusementpark.cpp:8:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |                 freopen(taskname".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 23
• Subtask 4: 0 / 21
• Subtask 5: 0 / 37