Submission #859766

#	Time	Username	Problem	Language	Result	Execution time	Memory
859766		dsyz	Combo (IOI18_combo)	C++17	100 / 100	15 ms	1932 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
using ll = long long;
#define MAXN (1000005)

std::string guess_sequence(int N) {
	string p = "AB";
	ll res = press(p);
	char firstchar = ' ';
	if(res >= 1){
		p = "A";
		res = press(p);
		if(res >= 1){
			firstchar = 'A';
		}else{
			firstchar = 'B';
		}
	}else{
		p = "X";
		res = press(p);
		if(res >= 1){
			firstchar = 'X';
		}else{
			firstchar = 'Y';
		}
	}
	string ans = "";
	ans.push_back(firstchar);
	vector<char> choices;
	if(firstchar != 'A') choices.push_back('A');
	if(firstchar != 'B') choices.push_back('B');
	if(firstchar != 'X') choices.push_back('X');
	if(firstchar != 'Y') choices.push_back('Y');
	for(ll i = 1;i < N - 1;i++){
		p = ans + choices[0] + choices[0];
		p += ans + choices[0] + choices[1];
		p += ans + choices[0] + choices[2];
		p += ans + choices[1];
		res = press(p);
		if(res == ans.size() + 2){
			ans.push_back(choices[0]);
		}else if(res == ans.size() + 1){
			ans.push_back(choices[1]);
		}else if(res == ans.size()){
			ans.push_back(choices[2]);
		}
	}
	if(N > 1){
		p = ans + choices[0];
		res = press(p);
		if(res == N){
			ans.push_back(choices[0]);
			return ans;
		}
		p = ans + choices[1];
		res = press(p);
		if(res == N){
			ans.push_back(choices[1]);
			return ans;
		}
		ans.push_back(choices[2]);
		return ans;
	}
	return ans;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:41:10: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |   if(res == ans.size() + 2){
      |      ~~~~^~~~~~~~~~~~~~~~~
combo.cpp:43:16: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |   }else if(res == ans.size() + 1){
      |            ~~~~^~~~~~~~~~~~~~~~~
combo.cpp:45:16: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |   }else if(res == ans.size()){
      |            ~~~~^~~~~~~~~~~~~

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