Submission #704923

#	Time	Username	Problem	Language	Result	Execution time	Memory
704923		PikaQ	Naboj (COCI22_naboj)	C++17	0 / 110	218 ms	32868 KiB

naboj

#include<bits/stdc++.h>
#define int long long
#define forn(i,n) for(int i = 0;i < n;i++)
#define Forn(i,n) for(int i = 1;i <= n;i++)
#define vi vector<int>
#define pb push_back
#define pii pair<int,int>
#define all(p) p.begin(),p.end()
#define F first
#define S second
using namespace std;
void debug() {cerr << endl;}
template <class T, class ...U> void debug(T a, U ... b) { cerr << a << " "; debug(b...);}
const int INF = 1e13 + 10;
const int MOD = (int) 998244353;
const int N = 2e5 + 9;
int n,m;
vi e1[N];
vector<pii> e2[N];
int in[N],out[N];
vector<pii> ans;
queue<int> que;
bool vis[N];
bool tag[N];
void dfs(int u,int tp){
	vis[u] = 1;
	ans.pb({u,tp});
	if(tp) tp = 0;
	else tp = 1;
	for(auto [c,w] : e2[u]){
		if(!vis[c] && w == tp){
			dfs(c,tp);
		}
	}
}


bool dfsc(int u){
	//debug(u);
	vis[u] = 1;
	tag[u] = 1;
	bool ok = 0;
	for(int c : e1[u]){
		if(tag[c]) ok = 1;
		else if(vis[c]) continue;
		else ok |= dfsc(c); 
	}
	tag[u] = 0;
	return ok;
}

void solve(){
	//pancake ( ^-^)_	
	cin >> n >> m;
	forn(i,m){
		int s,t;
		cin >> s >> t;
		out[s]++,in[t]++;
		e1[s].pb(t);
		e2[s].pb({t,1});
		e2[t].pb({s,0});
	}
	//debug("?");
	Forn(i,n) if(!vis[i] && dfsc(i)) {
		cout << "-1\n";
		return ;
	}
	Forn(i,n) vis[i] = 0;
	Forn(i,n){
		if(!vis[i] && out[i]) dfs(i,0);
		else if(!vis[i] && in[i]) dfs(i,1);
	}
	cout << ans.size() << '\n';
	forn(i,ans.size()){
		cout << ans[i].F << ' ' << ans[i].S << '\n';
	}
}

signed main(){
	cin.tie(NULL);
	cout.tie(NULL);
	ios_base::sync_with_stdio(0);
	solve();
	return 0;
}







	

Compilation message (stderr)

naboj.cpp: In function 'void solve()':
naboj.cpp:3:35: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    3 | #define forn(i,n) for(int i = 0;i < n;i++)
......
   74 |  forn(i,ans.size()){
      |       ~~~~~~~~~~~~                 
naboj.cpp:74:2: note: in expansion of macro 'forn'
   74 |  forn(i,ans.size()){
      |  ^~~~

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