Submission #77563

#	Time	Username	Problem	Language	Result	Execution time	Memory
77563		scanhex	Combo (IOI18_combo)	C++17	100 / 100	74 ms	624 KiB

combo

#include <bits/stdc++.h>

using namespace std;

#include "combo.h"

using arr = array<bool, 4>;

std::string guess_sequence(int N) {
	string ss = "XYAB";
	int L = 0, R = 4;
	while (R - L > 1)
	{
		int M = (L + R) / 2;
		string s;
		for (int i = L; i < M; ++i)
			s.push_back(ss[i]);
		if (press(s) >= 1)
			R = M;
		else
			L = M;
	}
	string cur;
	cur.push_back(ss[L]);
	if (N == 1)
		return cur;
	string s = "XYAB";
	s.erase(find(s.begin(), s.end(), cur[0]));
	for (int i = 1; i < N - 1; ++i)
	{
		string que = cur;
		que.push_back(s[0]);
		for (int j = 0; j < 3; ++j)
		{
			que += cur;
			que.push_back(s[1]);
			que.push_back(s[j]);
		}
		int mem = press(que);
		if (mem == i)
			cur.push_back(s[2]);
		else if (mem == i + 1)
			cur.push_back(s[0]);
		else
			cur.push_back(s[1]);
	}
	for (int i = 0; i < 2; ++i)
	{
		string que = cur;
		que.push_back(s[i]);
		if (press(que) == N)
		{
			 cur = que;
			 break;
		}
	}
	if (cur.size() < N)
		cur.push_back(s.back());
	return cur;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:57:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   57 |  if (cur.size() < N)
      |      ~~~~~~~~~~~^~~

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