Submission #102843

#	Time	Username	Problem	Language	Result	Execution time	Memory
102843		wxh010910	Combo (IOI18_combo)	C++17	100 / 100	58 ms	660 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"

using namespace std;

string guess_sequence(int n) {
  string alphabet = "ABXY", answer = "";
  int first_letter = press("AB");
  if (first_letter) {
    if (press("A")) {
      first_letter = 0;
      answer = "A";
    } else {
      first_letter = 1;
      answer = "B";
    }
  } else {
    if (press("X")) {
      first_letter = 2;
      answer = "X";
    } else {
      first_letter = 3;
      answer = "Y";
    }
  }
  if (n == 1) {
    return answer;
  }
  for (int i = 0; i < n - 2; ++i) {
    int current = 0;
    string query = "";
    for (int j = 0; j < 4; ++j) {
      if (j != first_letter) {
        if (current == 1) {
          query += answer + alphabet[j];
        } else if (current == 2) {
          for (int k = 0; k < 4; ++k) {
            if (k != first_letter) {
              query += answer + alphabet[j] + alphabet[k];
            }
          }
        }
        ++current;
      }
    }
    int result = press(query);
    current = answer.length();
    for (int j = 0; j < 4; ++j) {
      if (j != first_letter) {
        if (result == current) {
          answer += alphabet[j];
        }
        ++current;
      }
    }
  }
  if (press(answer + "A" + answer + "B") == n) {
    if (press(answer + "A") == n) {
      return answer + "A";
    } else {
      return answer + "B";
    }
  } else {
    if (press(answer + "X") == n) {
      return answer + "X";
    } else {
      return answer + "Y";
    }
  }
}

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