Submission #638640

#	Time	Username	Problem	Language	Result	Execution time	Memory
638640		rockoana	Combo (IOI18_combo)	C++17	100 / 100	37 ms	588 KiB

combo

#include "combo.h"
using namespace std;

std::string guess_sequence(int N) {
  int n = N;
  string res = "";
  string lft = "";

  // first letter
  string q = "AB";
  int c = press(q);

  if (c >= 1) {
    q = "B";
    c = press(q);
    if (c) {
      res += 'B';
      lft = "AXY";
    } else {
      res += 'A';
      lft = "BXY";
    }
  } else {
    q = "X";
    c = press(q);
    if (c) {
      res += 'X';
      lft = "ABY";
    } else {
      res += 'Y';
      lft = "ABX";
    }
  }

  if (n == 1) {
    return res;
  }

  // next letters
  while (res.size() < n - 1) {
    q = res + lft[0];

    q += res + lft[1] + lft[1];
    q += res + lft[1] + lft[0];
    q += res + lft[1] + lft[2];

    c = press(q);
    if (c == res.size()) {
      res += lft[2];
    } else if (c == res.size() + 1) {
      res += lft[0];
    } else {
      res += lft[1];
    }
  }

  // last letter
  q = res + lft[0];
  q += res + lft[1];

  c = press(q);
  if (c == n) {
    q = res + lft[0];
    c = press(q);
    if (c == n) {
      res += lft[0];
    } else {
      res += lft[1];
    }
  } else {
    res += lft[2];
  }

  return res;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:40:21: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   40 |   while (res.size() < n - 1) {
      |          ~~~~~~~~~~~^~~~~~~
combo.cpp:48:11: 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 (c == res.size()) {
      |         ~~^~~~~~~~~~~~~
combo.cpp:50:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |     } else if (c == res.size() + 1) {
      |                ~~^~~~~~~~~~~~~~~~~

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