Submission #292263

#	Time	Username	Problem	Language	Result	Execution time	Memory
292263		ahadviger	Combo (IOI18_combo)	C++14	97 / 100	42 ms	700 KiB

combo

#include "combo.h"
#include <iostream>

std::string guess_sequence(int N) {
  std::string p = "";
  std::string S = "";
  std::string a, b, c;

  if (N == 1) {
    if (press("A") == 1) return "A";
    if (press("B") == 1) return "B";
    if (press("X") == 1) return "X";
    if (press("Y") == 1) return "Y";
  }
 
  p = "AB";
  int res = press(p);

  if (res > 0) {
    p = "AXAYAAAB";
    res = press(p);
    if (res == 2) {
      S = "A";
      a = "B"; b = "X", c = "Y";
    } else {
      S = "B";
      a = "A"; b = "X", c = "Y";
    }
  } else {
    p = "XAXBXXXY";
    res = press(p);
    if (res == 2) {
      S = "X";
      a = "B"; b = "A", c = "Y";
    } else {
      S = "Y";
      a = "B"; b = "X", c = "A";
    }
  }

  for (int i = 1; i < N - 1; ++i) {
    p = S + a + a + S + a + b + S + a + c + S + b;
    res = press(p);
    if (res == i + 2) S += a;
    if (res == i + 1) S += b;
    if (res == i) S += c;
  }

  p = S + a;
  if (press(p) == N) return p;
  p = S + b;
  if (press(p) == N) return p; 

  return S + c;
}

• Subtask 1: 5 / 5
• Subtask 2: 92 / 95