Submission #776278

#	Time	Username	Problem	Language	Result	Execution time	Memory
776278		Lobo	Combo (IOI18_combo)	C++17	100 / 100	28 ms	592 KiB

combo

#include "combo.h"
#include<bits/stdc++.h>

using namespace std;

string guess_sequence(int N) {
	string ans;
	string a = "ABXY";
	// for(int i = 0; i < 4; i++) {
	// 	if(i == 3) {
	// 		ans = a[i];
	// 		a.erase(a.begin()+i,a.begin()+i+1);
	// 		break;
	// 	}
	// 	string ask;
	// 	ask+= a[i];
	// 	if(press(ask)) {
	// 		ans = a[i];
	// 		a.erase(a.begin()+i,a.begin()+i+1);
	// 		break;
	// 	}
	// }

	if(press(ans+a[0]+a[1]) > 0) {
		if(press(ans+a[0])) {
			ans = a[0];
			a = "BXY";
		}
		else {
			ans = a[1];
			a = "AXY";
		}
	}
	else {
		if(press(ans+a[2])) {
			ans = a[2];
			a = "ABY";
		}
		else {
			ans = a[3];
			a = "ABX";
		}
	}

	if(N == 1) return ans;

	for(int i = 1; i < N-1; i++) {
		string ask;
		ask = ans + a[0] + a[0];
		ask+= ans + a[0] + a[1];
		ask+= ans + a[0] + a[2];
		ask+= ans + a[1];


		int c = press(ask);
		if(c == ans.size()) ans+= a[2];
		else if(c == ans.size()+1) ans+= a[1];
		else if(c == ans.size()+2) ans+= a[0];
		else assert(false);
	}

	if(press(ans+a[0]) == N) return ans+a[0];
	else if(press(ans+a[1]) == N) return ans+a[1];
	else return ans+a[2];
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:56:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   if(c == ans.size()) ans+= a[2];
      |      ~~^~~~~~~~~~~~~
combo.cpp:57:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |   else if(c == ans.size()+1) ans+= a[1];
      |           ~~^~~~~~~~~~~~~~~
combo.cpp:58:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |   else if(c == ans.size()+2) ans+= a[0];
      |           ~~^~~~~~~~~~~~~~~

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