제출 #572697

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
572697		piOOE	Amusement Park (CEOI19_amusementpark)	C++17	19 / 100	3072 ms	336 KiB

amusementpark

#include <bits/stdc++.h>

using namespace std;

#define sz(x) ((int)size(x))
#define all(x) begin(x), end(x)
#define trace(x) cout << #x << ": " << (x) << endl;

typedef long long ll;

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

int rand(int l, int r) { return (int) ((ll) rnd() % (r - l + 1)) + l; }

const int N = 18, M = N * (N - 1) / 2, mod = 998244353;

vector<int> g[N], rg[N], new_g[N];
bool used[N];

int A[M], B[M], tp[N];

bool dfs(int v) {
    tp[v] = 1;
    for (int to : new_g[v]) {
        if (!tp[to]) {
            if (dfs(to)) {
                return true;
            }
        } else if (tp[to] == 1){
            return true;
        }
    }
    tp[v] = 2;
    return false;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        --a, --b;
        A[i] = a, B[i] = b;
        g[a].push_back(b);
        rg[b].push_back(a);
    }
    int ans = 0;
    for (int mask = 1; mask < (1 << m); ++mask) {
        for (int i = 0; i < n; ++i) {
            new_g[i].clear();
        }
        memset(tp, 0, sizeof(tp));
        int sum = 0;
        for (int i = 0; i < m; ++i) {
            if (mask & 1 << i) {
                new_g[B[i]].push_back(A[i]);
                ++sum;
            } else {
                new_g[A[i]].push_back(B[i]);
            }
        }
        bool ok = true;
        for (int i = 0; i < n; ++i) {
            if (!tp[i] && ok) {
                ok &= !dfs(i);
            }
        }
        if (ok) {
            ans += sum;
            ans %= mod;
        }
    }
    cout << ans;
    return 0;
}

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