Submission #491336

#	Time	Username	Problem	Language	Result	Execution time	Memory
491336		cfalas	Combo (IOI18_combo)	C++17	5 / 100	1 ms	200 KiB

combo

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

char letters[4] = {'A','B','X','Y'};
char first;
char next(int s){
	int fi=-1;
	for(int i=0;i<4;i++) 
		if(letters[i]==first) fi = i;
	return letters[(fi + s)%4];
}

string guess_sequence(int N) {
	string s = "";


	int x = press("AB");
	if(x>=1){
		if(x == 2) s = "AB";
		else if(press("A")==1) s = "A";
		else s = "B";
	}
	else{
		if(press("X")==1) s = "X";
		else s = "Y";
	}
	first = s[0];

	while((int)s.size()<N-1){
		string q = s + next(1);
		q += s + next(2) + next(1);
		q += s + next(2) + next(2);
		q += s + next(2) + next(3);
		//cout<<q<<endl;
		int x =press(q);
		if(x==s.size()) s += next(3);
		else if(x==s.size()+1) s+= next(1);
		else s+=next(2);
	}
	if(press(s+next(1))==N) s+=next(1);
	else if(press(s+next(2))==N) s+=next(2);
	else s+=next(3);
	return s;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:37:7: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |   if(x==s.size()) s += next(3);
      |      ~^~~~~~~~~~
combo.cpp:38:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |   else if(x==s.size()+1) s+= next(1);
      |           ~^~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 95