Submission #699192

#	Time	Username	Problem	Language	Result	Execution time	Memory
699192		beepbeepsheep	Naboj (COCI22_naboj)	C++17	0 / 110	268 ms	44176 KiB

naboj

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

typedef tree<long long, null_type, less_equal<>,
        rb_tree_tag, tree_order_statistics_node_update>
        ordered_set;
#define ll long long
#define ii pair<ll,ll>
#define endl '\n'

const ll inf=1e15;
const ll maxn=2e5+5;
const ll mod=1e9+7;

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

ll cnt[maxn][2];
bool vis[maxn];
set<ii> adj[maxn];
queue<ii> q;
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	ll n,m,a,b;
	cin>>n>>m;
	for (int i=0;i<m;i++){
		cin>>a>>b;
		adj[a].emplace(b,0);
		adj[b].emplace(a,1);
		cnt[a][0]++;
		cnt[b][1]++;
	}
	for (int i=1;i<=n;i++){
		if (cnt[i][0]==0){
			q.emplace(i,0);
		} else if (cnt[i][1]==0){
			q.emplace(i,1);
		}
	}
	stack<ii> s;
	while (q.size()){
		tie(a,b)=q.front();
		q.pop();
		for (auto [x,y]:adj[a]){
			adj[x].erase(make_pair(a,b));
			if (cnt[x][b]==1 && vis[x]==0){
				q.emplace(x,y);
				vis[x]=1;
			}
			cnt[x][b]--;
		}
		s.emplace(a,b);
	}
	for (int i=1;i<=n;i++){
		if (cnt[i][0] && cnt[i][1]){
			cout<<-1;
			return 0;
		}
	}
	cout<<s.size()<<endl;
	while (s.size()){
		cout<<s.top().first<<' '<<s.top().second<<endl;
		s.pop();
	}
	return 0;
}

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