Submission #990026

#	Time	Username	Problem	Language	Result	Execution time	Memory
990026		mannshah1211	Combo (IOI18_combo)	C++17	100 / 100	20 ms	1912 KiB

combo

/**
 *    author: tourist
 *    created:
**/
#include "combo.h"
#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "algo/debug.h"
#else
#define debug(...) 42
#endif

vector<string> alphabet = {"A", "B", "X", "Y"};

string guess_sequence(int n) {
  string firs = "?", ans;
  if (press("AB") >= 1) {
    if (press("A") == 1) {
      firs = "A";
    } else {
      firs = "B";
    }
  } else {
    if (press("X") == 1) {
      firs = "X";
    } else {
      firs = "Y";
    }
  }
  ans += firs;
  if (n == 1) {
    return ans;
  }
  vector<int> possible;
  for (int i = 0; i < 4; i++) {
    if (alphabet[i] != firs) {
      possible.push_back(i);
    }
  }
  for (int i = 1; i < n - 1; i++) {
    int x = press(ans + alphabet[possible[0]] + ans + alphabet[possible[1]] + alphabet[possible[0]] + ans + alphabet[possible[1]] + alphabet[possible[1]] + ans + alphabet[possible[1]] + alphabet[possible[2]]);
    if (x == i) {
      ans += alphabet[possible[2]];
    } else if (x == i + 1) {
      ans += alphabet[possible[0]];
    } else {
      ans += alphabet[possible[1]];
    }
  }
  if (press(ans + alphabet[possible[0]]) == n) {
    ans += alphabet[possible[0]];
    return ans;
  }
  if (press(ans + alphabet[possible[1]]) == n) {
    ans += alphabet[possible[1]];
    return ans;
  }
  ans += alphabet[possible[2]];
  return ans;
}

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