Submission #251631

#	Time	Username	Problem	Language	Result	Execution time	Memory
251631		terencehill	Lutrija (COCI19_lutrija)	C++14	42 / 70	2092 ms	524292 KiB

lutrija

#include <bits/stdc++.h>
#define all(X) (X).begin(),(X).end()
#define rall(X) (X).rbegin(),(X).rend()
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define ff first
#define ss second
#define P 1000000007
#define in(x, a, b) (a <= x && x < b)

using namespace std;
using ll = long long;
typedef pair<int, int> ii;
typedef vector<ii> vii; 
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
const ll inf = 1000000001, INF = (ll)1e18 + 1;

bool isprime(ll x) {
	if(x == 0 || x == 1) return false;
	for(ll i = 2; i * i <= x; i++) if(x % i == 0) return false;
	return true;
}

ll a, b;
vi vis, ans;
vvi adj;
vector<ll> primes;
int done = 0;

void dfs(int node) {
	if(done) return;
	if(vis[node]) return;
	vis[node] = 1;
	if(primes[node] == b) {
		cout << ans.size() << endl;
		for(int i : ans) cout << i << " ";
		cout << endl;
		done = 1;
		return;
	}
	
	for(int i : adj[node]) {
		ans.pub(primes[i]);
		dfs(i);
		ans.pob();
		if(done) return;
	}  
	
	if(done) return;
}

int main() {
//	freopen("INSERT_NAME_HERE.in", "r", stdin);
//	freopen("INSERT_NAME_HERE.out", "w", stdout);

	cin >> a >> b;
	
	for(int i = a - 2; i <= a + 2; i += 2) if(isprime(i)) primes.push_back(i); 
	for(int i = b - 2; i <= b + 2; i += 2) if(isprime(i)) primes.push_back(i);
	
	primes.pub(2);
	sort(all(primes));
	primes.erase(unique(all(primes)), primes.end());
	
	adj.resize(primes.size());
	vis.resize(primes.size(), 0);
	for(int i = 0; i < primes.size(); i++) {
		for(int j = i + 1; j < primes.size(); j++) {
			if(isprime(primes[j] - primes[i])) {
				adj[i].pub(j);
				adj[j].pub(i);
			}
		}
	}
	
	for(int i = 0; i < primes.size(); i++) {
		if(primes[i] == a) {
			ans.pub(a);
			dfs(i);
			break;
		}
	}
	
	if(!done) cout << -1 << endl;
	
	return 0;
}

Compilation message (stderr)

lutrija.cpp: In function 'int main()':
lutrija.cpp:71:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < primes.size(); i++) {
                 ~~^~~~~~~~~~~~~~~
lutrija.cpp:72:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = i + 1; j < primes.size(); j++) {
                      ~~^~~~~~~~~~~~~~~
lutrija.cpp:80:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < primes.size(); i++) {
                 ~~^~~~~~~~~~~~~~~

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