Submission #588466

#	Time	Username	Problem	Language	Result	Execution time	Memory
588466		Blagojce	Potemkin cycle (CEOI15_indcyc)	C++11	30 / 100	1088 ms	2732 KiB

indcyc

#include <bits/stdc++.h>
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define st first
#define nd second
#define pb push_back
#define pq priority_queue
#define all(x) begin(x), end(x)

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;

const int mxn = 1003;
mt19937 _rand(time(NULL));

int n, m;
vector<int> g[mxn];		
		
int dep[mxn];	
int state[mxn];
int D[mxn];
int L[mxn];

int parent[mxn];
bool adj[mxn][mxn];

void dfs(int u){
	state[u] = 1;
	vector<int> restore;
	restore.resize(g[u].size());
	fr(i, 0, (int)g[u].size()){
		auto e = g[u][i];
		restore[i] = L[e];
		
	}
	for(auto e : g[u]){
		if(state[e] == 1 && e != parent[u]){
			L[e] = min(L[e], dep[u]);
		}
	}
	for(auto e : g[u]){
		if(state[e] == 2) continue;
		if(state[e] == 0){
			dep[e] = dep[u] + 1;
			parent[e] = u;
			dfs(e);
		}
		else if(e != parent[u]){
			D[u] = max(D[u], dep[e]);	
		}
	}
	
	for(auto e : g[u]){
		if(state[e] != 1 || dep[u] - dep[e] < 3) continue;
		
		int x = u;
		bool ok = true;
		while(dep[x] >= dep[e]){
			if(x == u || x == e){
				if(L[x] < dep[u] || dep[e] < D[x]){
					ok = false;
					break;
				}
			}
			else{
				if((L[x] != 1e6 && L[x] <= dep[u]) || (D[x] !=-1e6 && dep[e] <= D[x])){
					ok = false;
					break;
				}
			}
			if(x == parent[x]) break;
			x = parent[x];
		}
		if(ok){
			x = u;
			vector<int> sol;
			while(dep[x] >= dep[e]){
				sol.pb(x);
				if(x == parent[x]) break;
				x = parent[x];
				
			}
			reverse(all(sol));
			
			for(auto u : sol) cout<<u+1<<' ';
			cout<<endl;
			exit(0);
		}
	}
	fr(i, 0, (int)g[u].size()){
		auto e = g[u][i];
		L[e] = restore[i];
	}
	state[u] = 2;
}
		
int main(){
	cin >> n >> m;
	fr(i, 0, m){
		int u, v;
		cin >> u >> v;
		--u, --v;
		g[u].pb(v);
		g[v].pb(u);
		adj[u][v] = adj[v][u] = true;
	}
	fr(i, 0, n){
		shuffle(all(g[i]), _rand);
	}
	
	fr(i, 0, n){
		fr(j, 0, n) state[j] = 0, dep[j] = -1e6, D[j] = -1e6, L[j] = 1e6, parent[j] = j;
		dep[i] = 0;
		dfs(i);
	}
	cout<<"no"<<endl;
}
/*
6 8
1 2
2 3
3 4
2 5
6 1
5 6
4 2
4 1


*/

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