Submission #433851

#	Time	Username	Problem	Language	Result	Execution time	Memory
433851		frodakcin	Combo (IOI18_combo)	C++11	100 / 100	52 ms	476 KiB

combo

#include "combo.h"
#include <cstdio>

char btn[]="ABXY";

std::string guess_sequence(int N) {
  std::string p = "";

	int first=0;
	first |= !!press("BY");
	first |= !!press("XY")<<1;
	std::string poss="";
	for(int i=0;i<4;++i)
		if(i!=first)
			poss.push_back(btn[i]);

  std::string S = "";
	S += btn[first];
	for(int i=1;i+1<N;++i)
	{
		p="";
		p += (S+poss[1]);
		p += (S+poss[2]+poss[0]);
		p += (S+poss[2]+poss[1]);
		p += (S+poss[2]+poss[2]);
		S += poss[press(p)-i];
	}
	if(N>1)
	{
		int last=0;
		for(;last<2;++last)
			if(press(S+poss[last])==N)
				break;
		S += poss[last];
	}

  return S;
}

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95