Submission #959853

#	Time	Username	Problem	Language	Result	Execution time	Memory
959853		mansur	Newspapers (CEOI21_newspapers)	C++17	8 / 100	73 ms	27992 KiB

newspapers

//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
 
#include<bits/stdc++.h>	
 
using namespace std;
 
#define all(a) a.begin(), a.end()                                                   
#define rall(a) a.rbegin(), a.rend()                 
#define sz(a) (int)a.size()
#define s second
#define f first
 
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
 
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
     
vector<pii> rid = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
vector<pii> dir = {{-1, -1}, {-1, 1}, {1, -1}, {1, 1}};
 
const int N = 2e5 + 1, mod = 1e9 + 7;
 
const ll inf = 2e9;
 
double eps = 1e-15;
                                                
bool flg = 0;
 
vector<int> gr(N), st[1 << 20];
int n, m, was[1 << 20];

vector<int> f(int msk) {
	if (was[msk]) return st[msk];
	if (!msk) return {};
	was[msk] = 1;
	vector<int> ans(101); 
	st[msk] = ans;                  	
	vector<int> s;
	for (int i = 0; i < n; i++) {
		if (msk >> i & 1) {
			s.push_back(i);
		}	
	}
	vector<int> pr(sz(s)), sf(sz(s));
	for (int i = 0; i < sz(s); i++) {
		if (i) pr[i] = pr[i - 1];
		pr[i] |= gr[s[i]];
	}
	for (int i = sz(s) - 1; i >= 0; i--) {
		if (i < sz(s) - 1) sf[i] = sf[i + 1];
		sf[i] |= gr[s[i]];
	}
	for (int i = 0; i < sz(s); i++) {
		int mask = 0;
		if (i) mask |= pr[i - 1];
		if (i < sz(s) - 1) mask |= sf[i + 1];
		vector<int> x = f(mask);
		x.push_back(s[i]);
		if (sz(x) < sz(ans)) ans = x;
	}
	st[msk] = ans;
	return ans;
}
                                        	
void slv() {
	cin >> n >> m;
	if (m > n - 1) {
		cout << "NO";
		return;
	}
	vector<int> g[n];
	for (int i = 1; i <= m; i++) {
		int u, v;
		cin >> u >> v;
		u--, v--;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	if (n <= 9) {
		for (int i = 0; i < n; i++) {
			for (int to: g[i]) {
				gr[i] |= (1 << to);
			}
		}
		vector<int> ans = f((1 << n) - 1);
		if (sz(ans) > 5 * n) cout << "NO\n";
		else {
			reverse(all(ans));
			cout << "YES\n" << sz(ans) << '\n';
			for (int x: ans) cout << x + 1 << ' ';
		}
		return;
	}
	vector<int> s, ans;
	for (int i = 1; i <= n; i++) s.push_back(i);
	for (int i = 1; i <= 10 * n && sz(s); i++) {
		int pos = min(sz(s) - 1, 1);
		ans.push_back(s[pos]);
		vector<bool> is(n + 2);
		for (int j = 0; j < sz(s); j++) {
			if (j == pos) continue;
			is[s[j] - 1] = is[s[j] + 1] = 1;
		}
		s.clear();
		for (int i = 1; i <= n; i++) {
			if (is[i]) s.push_back(i);
		}
	}
	cout << "YES\n";
	cout << (n - 2) * 2 << '\n';
	for (int i = 2; i < n; i++) cout << i << ' ';
	if (n & 1) {
		for (int i = 2; i < n; i++) cout << i << ' ';
	}else {	
		for (int i = n - 1; i >= 2; i--) cout << i << ' ';
	}
}                                                                           
 
main() {
	//freopen("input.txt", "r", stdin);                                                                                     
	//freopen("output.txt", "w", stdout);                                                                                     
	ios_base::sync_with_stdio(0);	                                                                                       
	cin.tie(0);
	int tp = 1;
	if (flg) cin >> tp;
	while (tp--) {  	
		slv();
	}
}
//wenomechainsama      

Compilation message (stderr)

newspapers.cpp:121:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  121 | main() {
      | ^~~~

• Subtask 1: 0 / 12
• Subtask 2: 8 / 8
• Subtask 3: 0 / 80