Submission #988900

#	Time	Username	Problem	Language	Result	Execution time	Memory
988900		lo0ker	Combo (IOI18_combo)	C++17	5 / 100	1 ms	344 KiB

combo

#include "combo.h"

using namespace std;


string guess_sequence(int N) {
  if(N == 1){
    if(press("A") == 1){
      return "A";
    }
    else if(press("B") == 1){
      return "B";
    }
    else if(press("X") == 1){
      return "X";
    }
    else "Y";
  }
  string prefix = "";
  char o1, o2, o3;
  if(press("A") == 1){
    prefix = "A";
    o1 = 'B';
    o2 = 'X';
    o3 = 'Y';
  }
  else if(press("B") == 1){
    prefix = "B";
    o1 = 'A';
    o2 = 'X';
    o3 = 'Y';
  }
  else if(press("X") == 1){
    prefix = "X";
    o1 = 'A';
    o2 = 'B';
    o3 = 'Y';
  }
  else{
    prefix = "Y";
    o1 = 'A';
    o2 = 'B';
    o3 = 'X';
  }

  while(prefix.size() < N-1){
    string q = prefix + o1 + prefix + o2 + o1 + prefix + o2 + o2 + prefix + o2 + o3;
    if(press(q) == prefix.size()+1){
      prefix += o1;
    }
    else if(press(q) == prefix.size()+2){
      prefix += o2;
    }
    else{
      prefix += o3;
    }
  }
  if(press(prefix + o1) == N){
    prefix += o1;
  }
  else if(press(prefix + o2) == N){
    prefix += o2;
  }
  else{
    prefix += o3;
  }
  return prefix;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:17:10: warning: statement has no effect [-Wunused-value]
   17 |     else "Y";
      |          ^~~
combo.cpp:46:23: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   46 |   while(prefix.size() < N-1){
      |         ~~~~~~~~~~~~~~^~~~~
combo.cpp:48:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     if(press(q) == prefix.size()+1){
      |        ~~~~~~~~~^~~~~~~~~~~~~~~~~~
combo.cpp:51:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     else if(press(q) == prefix.size()+2){
      |             ~~~~~~~~~^~~~~~~~~~~~~~~~~~

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