Submission #971062

#	Time	Username	Problem	Language	Result	Execution time	Memory
971062		ALeonidou	Thousands Islands (IOI22_islands)	C++17	6.75 / 100	24 ms	5212 KiB

islands

#include "islands.h"

#include <set>
#include <variant>
#include <vector>
#include <iostream>
using namespace std;

#define ll int
#define F first
#define S second
#define pb push_back
#define sz(x) (ll)x.size()
#define endl "\n"

typedef vector <ll> vi;
typedef pair <ll, ll> ii;
typedef vector <ii> vii;
	
#define dbg(x) cout<<#x<<": "<<x<<endl;
#define dbg2(x,y) cout<<#x<<": "<<x<<" "<<#y<<": "<<y<<endl;
#define dbg3(x,y,z) cout<<#x<<": "<<x<<" "<<#y<<": "<<y<<" "<<#z<<": "<<z<<endl;
	
void printVct(vi &v){
	for (ll i =0; i<sz(v); i++){
			cout<<v[i]<<" ";
	}
	cout<<endl;
}

ll n,m;
vi u,v;

variant<bool, vi> find_journey(int N, int M, vi U, vi V){
	ll n = N, m = M;
	u = U, v = V;
	// printVct(u);
	// printVct(v);
	if (n == 2){
		ll f0 = 0, f1= 0;
		vi a(3,-1);
		for (ll i =0; i<m; i++){
			if (!u[i]){
				f0++;
				if (a[0] == -1){
					a[0] = i;
				}
				else if (a[1] == -1){
					a[1] = i;
				}
			}
			else{
				f1++;
				if (a[2] == -1){
					a[2] = i;
				}
			}
		}
		// dbg2(f0, f1);
		// printVct(a);

		if (f0 >= 2 && f1 >= 1){
			return vi({a[0], a[2], a[1], a[0], a[2], a[1]});
		}
		else{
			return false;
		}
	}
	else{
		//subtask 2:
		set <ll> st;
		vii a;	//with boat S you go from 0 to F
		for (ll i =0; i<m; i++){
			if (u[i] == 0 && st.find(v[i]) == st.end()){
				st.insert(v[i]);
				a.pb(ii(v[i], i));
			}
			if (sz(a) >= 2) break;
		}
		// dbg(sz(a));
		if (sz(a) < 2) return false;
		
		vi b = vi({-1, a[0].S, a[1].S, -1});
		for (ll i =0; i<n; i++){
			if (u[i] == a[0].F && v[i] == 0){
				b[0] = i;
			}
		}
		for (ll i =0; i<n; i++){
			if (u[i] == a[1].F && v[i] == 0){
				b[3] = i;
			}
		}
		// printVct(b);

		return vi({b[1], b[0], b[2], b[3], b[0], b[1], b[3], b[2]});
	}
	return false;
}

/*
3 4
0 1
1 0
2 0
0 2

2 3
0 1
1 0
1 0

2 3
0 1
0 1
1 0



*/

• Subtask 1: 5 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45