Submission #234346

#	Time	Username	Problem	Language	Result	Execution time	Memory
234346		eggag32	Lutrija (COCI19_lutrija)	C++17	0 / 70	161 ms	388 KiB

lutrija

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define debug(x) cerr << #x << ": " << x << endl;
#define debug2(x, y) debug(x) debug(y);
#define repn(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(i, a) for(int i = 0; i < (int)(a); i++)
#define all(v) v.begin(), v.end() 
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define sq(x) ((x) * (x))

template<class T> T gcd(T a, T b){ return ((b == 0) ? a : gcd(b, a % b)); }

bool prime(ll num){
	if(num <= 1) return 0;
	for(ll j = 2; (j * j) <= num; j++){
		if(num % j == 0) return 0;
	}
	return 1;
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	//freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
	ll a, b;
	cin >> a >> b;
	if(prime(abs(a - b))){
		cout << 2 << endl;
		cout << a << " " << b << endl;
		return 0;
	}
	if(prime(abs((a + 2) - b)) && prime(a + 2)){
		cout << 3 << endl;
		cout << a << " " << a + 2 << " " << b << endl;
		return 0;
	}
	if(prime(abs(a - (b + 2))) && prime(b + 2)){
		cout << 3 << endl;
		cout << a << " " << b + 2 << " " << b << endl;
		return 0;
	}
	if(prime(abs((a - 2) - b)) && prime(a - 2)){
		cout << 3 << endl;
		cout << a << " " << a - 2 << " " << b << endl;
		return 0;
	}
	if(prime(abs(a - (b - 2))) && prime(b - 2)){
		cout << 3 << endl;
		cout << a << " " << b - 2 << " " << b << endl;
		return 0;
	}
	//try to 'connect' it with 2's
	int rev = 0;
	if(a > b) swap(a, b), rev = 1;
	if((a - b) % 2 == 0 && (a - b) / 2 <= 29){
		vi ans;
		ll cur = a;
		int f = 1;
		while(cur <= b){
			if(!prime(cur)){
				f = 0;
				break;
			}
			ans.pb(cur);
			cur += 2;
		}
		if(f){
			cout << ans.size() << endl;
			if(rev) reverse(all(ans));
			rep(i, ans.size()) cout << ans[i] << " ";
			cout << endl;
			return 0;
		}
	}
	cout << -1 << endl;
	return 0;
}
/*
Things to look out for:
	- Integer overflows
	- Array bounds
	- Special cases
Be careful!
*/

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