Submission #781628

#	Time	Username	Problem	Language	Result	Execution time	Memory
781628		makanhulia	Naboj (COCI22_naboj)	C++17	0 / 110	480 ms	31764 KiB

naboj

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

# define int long long
# define fir first
# define sec second
# define pb push_back

const int cnst = 2e5+5;
bool mutipletestcase = 0;
//bool debug = false;

int x[cnst], y[cnst];
int dis[cnst];
vector<int> vec[cnst], vec2[cnst];


// void dfs(int x) {
//     for(auto v: vec[x]) {
//         if(dis[v] != 0) continue;
//         dis[v] = dis[x]+1;
//         dfs(v);
//     }
// }

void solve() {
    int n, m; cin >> n >> m;

    for(int i = 1; i<=m; i++) {
        int a, b; cin >> a >> b;
        vec[a].pb(b);
        vec2[b].pb(a);
        x[a]++; y[b]++;
    }

    // bool yes = 0;
    // for(int i = 1; i<=n; i++) if(!y[i]) yes = 1; 

    // if(!yes) {cout << "-1" << endl; return;}

    queue<int> q;
    int done = 0;

    for(int i = 1; i<=n; i++) {
        if(!x[i]) q.push(i), done++;
    }

    vector<pair<int, int>> ans;

    while(!q.empty()) {
        int a = q.front(); q.pop();

        for(auto v: vec2[a]) {
            x[v]--;
            if(!x[v]) {
                q.push(v);
                ans.pb({v, 1});
                done++;
            }
        }

        // cerr << a << " " << done << endl;
        if(done != n) ans.pb({a, 0});
        else break;
    }

    if(done == n) {
        cout << ans.size() << endl;
        for(auto v: ans) cout << v.fir << " " << v.sec << endl;
    }
    else cout << -1 << endl;

}

signed main() {
    ios_base::sync_with_stdio(false);
    int t = 1;
    if(mutipletestcase) cin >> t; 
    while(t--) solve();
}

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