Submission #878976

#	Time	Username	Problem	Language	Result	Execution time	Memory
878976		mahmoudbadawy	Cave (IOI13_cave)	C++17	100 / 100	165 ms	604 KiB

cave

#include "cave.h"

const int MX=5005;

int known[MX], state[MX], doors[MX];
int prev,n;

void ask()
{
	prev=tryCombination(state);
}

int find_key(int st,int en,int door)
{
	if(st==en) return st;
	int mid=(st+en)/2;
	int curp=prev;
	for(int i=st;i<=mid;i++)
	{
		if(!known[i]) state[i]^=1;
	}
	ask();
	if((curp==door)^(prev==door)) // Key in [st,mid]
		return find_key(st,mid,door);
	return find_key(mid+1,en,door);
}

void exploreCave(int N) {
	ask();
	n=N;
	for(int i=0;i<n;i++)
	{
		int key=find_key(0,n-1,i);
		if(prev==i)
		{
			state[key]^=1;
			ask();
		}
		known[key]=1;
		doors[key]=i;
	}
	answer(state,doors);
}

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