Submission #117126

#	Time	Username	Problem	Language	Result	Execution time	Memory
117126		exqt	Combo (IOI18_combo)	C++17	100 / 100	57 ms	536 KiB

combo

#include <vector>
#include <iostream>
using namespace std;

#include "combo.h"

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

  auto guess1 = [&S]() {
    if(press(S+"A"+S+"B") > S.length())
      if(press(S+"A") > S.length()) S += 'A'; else S += 'B';
    else
      if(press(S+"X") > S.length()) S += 'X'; else S += 'Y';
  };

  guess1();
  if(S.length() == N) return S;

  vector<char> candi;
  for(char c : "ABXY") {
    if(c != S[0]) candi.push_back(c);
  }

  auto guess2 = [&S, &candi]() {
    int t = press(
      S+candi[0]+candi[0]+
      S+candi[0]+candi[1]+
      S+candi[0]+candi[2]+
      S+candi[1]
    );

    if(t == S.length()+2) S += candi[0];
    else if(t == S.length()+1) S += candi[1];
    else S += candi[2];
  };

  for(int i=1; i<N-1; i++) guess2();
  guess1();

  return S;
}

Compilation message (stderr)

combo.cpp: In lambda function:
combo.cpp:11:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |     if(press(S+"A"+S+"B") > S.length())
      |        ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
combo.cpp:12:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |       if(press(S+"A") > S.length()) S += 'A'; else S += 'B';
      |          ~~~~~~~~~~~~~^~~~~~~~~~~~
combo.cpp:14:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |       if(press(S+"X") > S.length()) S += 'X'; else S += 'Y';
      |          ~~~~~~~~~~~~~^~~~~~~~~~~~
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:18:17: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   18 |   if(S.length() == N) return S;
      |      ~~~~~~~~~~~^~~~
combo.cpp: In lambda function:
combo.cpp:33:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |     if(t == S.length()+2) S += candi[0];
      |        ~~^~~~~~~~~~~~~~~
combo.cpp:34:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |     else if(t == S.length()+1) S += candi[1];
      |             ~~^~~~~~~~~~~~~~~

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