Submission #502531

#	Time	Username	Problem	Language	Result	Execution time	Memory
502531		InternetPerson10	Amusement Park (CEOI19_amusementpark)	C++17	19 / 100	3062 ms	324 KiB

amusementpark

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

bool bad[20][20];

const ll MOD = 998244353;

int main() {
    int n, m;
    cin >> n >> m;
    vector<pair<int, int>> edges(m);
    for(int i = 0; i < m; i++) {
        int x, y;
        cin >> x >> y;
        x--; y--;
        edges[i] = {x, y};
        bad[y][x] = true;
    }
    ll ans = 0;
    vector<int> nums(n);
    for(int i = 0; i < n; i++) nums[i] = i;
    for(int i = 0; i < (1 << m); i++) {
        vector<vector<int>> adj(n);
        for(int j = 0; j < m; j++) {
            if(i & (1 << j)) swap(edges[j].first, edges[j].second);
            adj[edges[j].first].push_back(edges[j].second);
        }
        bool ok = true;
        queue<int> q;
        vector<bool> done(n);
        for(int j = 0; j < n; j++) {
            if(adj[j].size() == 0) {
                q.push(j);
                done[j] = true;
            }
        }
        while(q.size()) {
            int p = q.front(); q.pop();
            for(int j = 0; j < n; j++) {
                for(int k = 0; k < adj[j].size(); k++) {
                    if(adj[j][k] == p) {
                        adj[j].erase(adj[j].begin() + k);
                        break;
                    }
                }
                if(adj[j].size() == 0 && !done[j]) {
                    q.push(j);
                    done[j] = true;
                }
            }
        }
        int g = 0;
        for(int j = 0; j < n; j++) {
            if(!done[j]) ok = false;
        }
        for(int j = 0; j < m; j++) {
            if(i & (1 << j)) {
                swap(edges[j].first, edges[j].second);
                g++;
            }
        }
        if(ok) ans += g;
    }
    cout << ans << '\n';
}

Compilation message (stderr)

amusementpark.cpp: In function 'int main()':
amusementpark.cpp:42:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |                 for(int k = 0; k < adj[j].size(); k++) {
      |                                ~~^~~~~~~~~~~~~~~

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