Submission #373597

#	Time	Username	Problem	Language	Result	Execution time	Memory
373597		cheissmart	Cave (IOI13_cave)	C++14	100 / 100	481 ms	876 KiB

cave

#include "cave.h"
#include <bits/stdc++.h>
#define F first
#define S second
#define PB push_back
#define MP MP make_pair
#define EB emplace_back
#define V vector
#define ALL(v) (v).begin(), (v).end()
#define debug(x) cerr << "LINE(" << __LINE__ << ") -> " << #x << " is " << (x) << endl

using namespace std;

typedef long long ll;
typedef pair<int, int> pi;
typedef V<int> vi;

const int INF = 1e9 + 7, N = 5005;

int s[N], d[N], done[N], n;

int ask() {
	int res = tryCombination(s);
	if(res == -1) res = INF;
	return res;
}

pi go(int i) { // find the switch that controls door i
	vi can;
	for(int i = 0; i < n; i++)
		if(!done[i]) 
			can.PB(i);
	auto inv = [&] (vi& v) {
		for(int i:v) {
			s[i] ^= 1;
		}
	};
	int x = ask();
	assert(x >= i);
	while(can.size() > 1) {
		int sz = can.size();
		vi l, r;
		for(int i = 0; i < sz / 2; i++) l.PB(can[i]);
		for(int i = sz / 2; i < sz; i++) r.PB(can[i]);
		inv(l);
		int y = ask();
		assert(y >= i);
		inv(l);
		if((x == i) == (y == i)) { // in r
			can = r;
		} else { // in l
			can = l;
		}
	}
	assert(can.size() == 1);
	int id = can[0], state = s[id];
	if(x == i) state ^= 1;
	return {id, state};
}

void exploreCave(int _n) {
	n = _n;
	for(int i = 0; i < n; i++) {
		 pi p = go(i); // {which switch, which state}
		 s[p.F] = p.S;
		 d[p.F] = i;
		 done[p.F] = 1;
	}
	answer(s, d);
}

• Subtask 1: 12 / 12
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 30 / 30
• Subtask 5: 24 / 24