Submission #781772

#	Time	Username	Problem	Language	Result	Execution time	Memory
781772		makanhulia	Naboj (COCI22_naboj)	C++17	25 / 110	424 ms	26868 KiB

naboj

#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define pii pair<int,int>
#define fr first
#define sc second
using namespace std;

const int N = 2e5+5;
const int M = 5e5+5;

vector<int> adj[N];
vector<int> opp[N];
vector<int> marker;
vector<int> par;
vector<int> keep;
vector<bool> vis;

bool dfs(int x) {
    marker[x] = 1;
    for (auto item : adj[x]) {
        if (!marker[item]) {
            par[item] = x;
            if (dfs(item)) return true;
        } else if (marker[item] == 1) return true;
    }
    marker[x] = 2;
    return false;
}

signed main() { 
    int n, m; cin >> n >> m;
    marker.assign(n+1, 0);
    par.assign(n+1, -1);
    vis.assign(n+1, 0);
    vector<pii> v;
    for (int i = 0; i < m; i++) {
        int a, b; cin >> a >> b;
        adj[b].pb(a);
        opp[a].pb(b);
    }
    for (int i = 1; i <= n; i++) {
        if (!marker[i]) {
            if (dfs(i)) {
                cout << -1 << endl;
                return 0;
            }
        }
    }
    
    for (int i = 1; i <= n; i++) {
        if (!vis[i]) {
            queue<int> q;
            q.push(i);

            while(!q.empty()) {
                int cur = q.front(); q.pop();
                vis[cur] = 1;
                if (adj[cur].size() == 0) {
                    for (auto item : opp[cur]) {
                        if (!vis[item]) {
                            q.push(item);
                            v.pb({item, 0});
                        }
                    }
                } else if (opp[cur].size() == 0) {
                    for (auto item : adj[cur]) {
                        if (!vis[item]) {
                            q.push(item);
                            v.pb({item, 1});
                        }
                    }
                }
                else {
                    bool pushed = false;
                    for (auto item : adj[cur]) {
                        if (!vis[item]) {
                            pushed = true;
                            q.push(item);
                            v.pb({item, 1});
                        }
                    }
                    if (pushed) {
                        for (auto item : opp[cur]) {
                            if (!vis[item]) {
                                q.push(item);
                                v.pb({item, 0});
                            }
                        }
                    } else {
                        bool pulled = false;
                        for (auto item : opp[cur]) {
                            if (!vis[item]) {
                                pulled = true;
                                q.push(item);
                                v.pb({item, 0});
                            }
                        }
                        if (pulled) {
                            for (auto item : adj[cur]) {
                                if (!vis[item]) {
                                    q.push(item);
                                    v.pb({item, 1});
                                }
                            }
                        }
                    }
                }
            }

        }
    }
    cout << v.size() << endl;
    for (auto item : v) cout << item.fr << " " << item.sc << endl;
}

• Subtask 1: 0 / 15
• Subtask 2: 25 / 25
• Subtask 3: 0 / 70