Submission #1172801

#	Time	Username	Problem	Language	Result	Execution time	Memory
1172801		Dan4Life	Potemkin cycle (CEOI15_indcyc)	C++20	80 / 100	1093 ms	1352 KiB

indcyc

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) begin(a),end(a)
using ll = long long;
using ar2 = array<ll,2>;
using vi = vector<int>;
const int mxN = (int)1e3+10;
const ll INF = (int)1e9;
const ll MOD = (ll)1e9+7;
int n, m, pos[mxN];
vi adj[mxN], v;
bitset<mxN> vis,skip;
bitset<mxN> edge[mxN];
 
 
void dfs2(int s, vi &v){
	vis[s] = 1; pos[s] = sz(v)-1;
	for(auto u : adj[s]){
		if(vis[u]) continue;
		vi w; w.clear();
		if(sz(adj[u])<sz(v)){
			for(auto x : adj[u]){
				if(pos[x]!=-1) w.pb(pos[x]);
				if(sz(w)==3) break;
			}
		}
		else{
			for(int i = 0; i < sz(v); i++){
				if(edge[v[i]][u]) w.pb(i);
				if(sz(w)==3) break;
			}
		}
		if(sz(w)==3) continue;
		if(sz(w)==2){
			sort(all(w));
			if(w[1]-w[0]==1) continue;
			for(int i = w[0]; i <= w[1]; i++)
				cout << v[i] << " ";
			cout << u << "\n";
			exit(0);
		} 
		v.pb(u); dfs2(u,v); v.pop_back(); pos[u]=-1;
	}
	if(n<=100) vis[s] = 0;
}

void dfs(int s){
	vis[s] = 1; pos[s] = sz(v)-1; skip[s]=1; v.pb(s);
	for(auto u : adj[s]){
		if(vis[u]) continue;
		vi w; w.clear();
		if(sz(adj[u])<sz(v)){
			for(auto x : adj[u]){
				if(pos[x]!=-1) w.pb(pos[x]);
				if(sz(w)==3) break;
			}
		}
		else{
			for(int i = 0; i < sz(v); i++){
				if(edge[v[i]][u]) w.pb(i);
				if(sz(w)==3) break;
			}
		}
		if(sz(w)==3) continue;
		if(sz(w)==2){
			sort(all(w));
			if(w[1]-w[0]==1) continue;
			for(int i = w[0]; i <= w[1]; i++)
				cout << v[i] << " ";
			cout << u << "\n";
			exit(0);
		} 
		dfs(u);
	}
	vis[s] = 0; pos[s] = -1; v.pop_back();
}
 
int main(){
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n >> m;
	for(int i = 0; i < m; i++){
		int a, b; cin >> a >> b;
		edge[a][b] = edge[b][a] = 1;
		adj[a].pb(b), adj[b].pb(a);
	}
	memset(pos,-1,sizeof(pos));
	if(n<=300){
		for(int i = 1; i <= n; i++){
			vis.reset(); v.pb(i); 
			dfs2(i,v); v.pop_back(); pos[i]=-1;
		}
		cout << "no\n"; return 0;
	}
	for(int i = 1; i <= n; i++)
		if(!skip[i]) dfs(i);
	cout << "no\n";
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 10 / 10
• Subtask 10: 0 / 10