Submission #489501

#	Time	Username	Problem	Language	Result	Execution time	Memory
489501		Evang	Combo (IOI18_combo)	C++17	100 / 100	43 ms	504 KiB

combo

#include <bits/stdc++.h>
using namespace std;
#include "combo.h"

string guess_sequence(int n) {
	string ans;
	if(press("AB")==0){
		if(press("X"))
			ans = "X";
		else
			ans = "Y";
	} else if(press("A"))
		ans = "A";
	else
		ans = "B";
	if(n==1)
		return ans;

	vector<string> v;
	for(const string &s: {"A", "B", "Y", "X"})
		if(s!=ans){
			v.push_back(s);
		}

	while(ans.size() + 1 < n){
		int x = press(ans + v[0] + v[0] + ans + v[0] + v[1] + ans + v[0] + v[2] + ans + v[1]);
		if(x==ans.size())
			ans += v[2];
		else if(x==ans.size()+1)
			ans += v[1];
		else
			ans += v[0];
	}

	if(press(ans + v[0] + ans + v[1])==ans.size()+1){
		if(press(ans+v[0])==ans.size()+1)
			return ans + v[0];
		return ans + v[1];
	}
	return ans + v[2];
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:25:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   25 |  while(ans.size() + 1 < n){
      |        ~~~~~~~~~~~~~~~^~~
combo.cpp:27:7: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |   if(x==ans.size())
      |      ~^~~~~~~~~~~~
combo.cpp:29:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |   else if(x==ans.size()+1)
      |           ~^~~~~~~~~~~~~~
combo.cpp:35:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |  if(press(ans + v[0] + ans + v[1])==ans.size()+1){
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
combo.cpp:36:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |   if(press(ans+v[0])==ans.size()+1)
      |      ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

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