Submission #97590

#	Time	Username	Problem	Language	Result	Execution time	Memory
97590		Retro3014	Potemkin cycle (CEOI15_indcyc)	C++17	70 / 100	1066 ms	2920 KiB

indcyc

#include <bits/stdc++.h>

#define pb push_back
#define all(v) ((v).begin(), (v).end())
#define sortv(v) sort(all(v))
#define sz(v) ((int)(v).size())
#define uniqv(v) (v).erase(unique(all(v)), (v).end())
#define umax(a, b) (a)=max((a), (b))
#define umin(a, b) (a)=min((a), (b))
#define FOR(i,a,b) for(int i = (a); i <= (b); i++)
#define rep(i,n) FOR(i,1,n)
#define rep0(i,n) FOR(i,0,(int)(n)-1)
#define FI first
#define SE second
#define INF 2000000000
#define INFLL 1000000000000000000LL


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

const int MAX_N = 1000;
const int MAX_M = 100000;

int N, M;
vector<int> gp[MAX_N+1];
vector<pii> edge;
bool chk[MAX_N+1];
bool chk2[MAX_N+1];
bool chkg[MAX_N+1];
int g[MAX_N+1];

int find_g(int x){
	if(x==g[x])	return x;
	return g[x] = find_g(g[x]);
}

void union_g(int x, int y){
	x = find_g(x), y = find_g(y);
	g[x] = y;
}

int from[MAX_N+1];
deque<int> dq;

void answer(int x, int y, int z, int w){
	from[y] = x; from[z] = y; from[w] = z;
	dq.pb(w);
	while(!dq.empty()){
		int now = dq.front();
		dq.pop_front();
		if(now==x)	break;
		for(auto i : gp[now]){
			if(i==x || (!chk[i] && find_g(i)==find_g(w))){
				if(from[i]==0){
					from[i] = now; dq.push_back(i);
				}
			}
		}
	}
	while(1){
		printf("%d ", x); if(x==y)	break;
		x = from[x];
	}
}


int main(){
	scanf("%d%d", &N, &M);
	rep(i, M){
		int a, b; scanf("%d%d", &a, &b);
		gp[a].pb(b); gp[b].pb(a);
		edge.pb({a, b});
	}
	rep(i, N){
		rep(j, N)	g[j] = j;
		chk[i] = true;
		for(auto j: gp[i])	chk[j] = true;
		for(auto p : edge){
			if(chk[p.first] || chk[p.second])	continue;
			union_g(p.first, p.second);
		}
		for(auto now : gp[i]){
			for(auto k : gp[now]){
				if(chk[k])	chk2[k] = true;
				else	chkg[find_g(k)] = true;
			}
			for(auto now2 : gp[i]){
				if(now2==now || chk2[now2])	continue;
				for(auto k : gp[now2]){
					if(chk[k])	continue;
					if(chkg[find_g(k)]){
						answer(now, i, now2, k);
						return 0;
					}
				}
			}
			for(auto k : gp[now]){
				if(chk[k])	chk2[k] = false;
				else	chkg[find_g(k)] = false;
			}
		}
		for(auto j : gp[i])	chk[j] = false;
		chk[i] = false;
	}
	printf("no");	return 0;
}

Compilation message (stderr)

indcyc.cpp: In function 'int main()':
indcyc.cpp:71:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &N, &M);
  ~~~~~^~~~~~~~~~~~~~~~
indcyc.cpp:73:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int a, b; scanf("%d%d", &a, &b);
             ~~~~~^~~~~~~~~~~~~~~~

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