Submission #690535

#	Time	Username	Problem	Language	Result	Execution time	Memory
690535		zeroesandones	Combo (IOI18_combo)	C++17	100 / 100	33 ms	884 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"
using namespace std;

using ll = long long;
using vi = vector<long long>;

#define pb emplace_back

std::string guess_sequence(int n) {
  char first = ' ';
  string res = "";

  vector<char> left;
  set<char> moves = {'A', 'B', 'X', 'Y'};

  int ab = press("AB");
  int ax = press("AX");
  if(ab && ax)
    first = 'A';
  else if(ab)
    first = 'B';
  else if(ax)
    first = 'X';
  else
    first = 'Y';

  res += first;
  moves.erase(first);
  for(auto i : moves)
    left.pb(i);

  if(n == 1) return res;

  for(int i = 1; i < n - 1; ++i) {
    string try1 = res + left[0];
    string try2 = res + left[1];
    string try21 = try2 + left[0];
    string try22 = try2 + left[1];
    string try23 = try2 + left[2];
    ll curr = press(try1 + try21 + try22 + try23);
    if(curr == i + 2)
      res += left[1];
    else if(curr == i + 1)
      res += left[0];
    else
      res += left[2];
  }

  ll try1 = press(res + left[0]);
  if(try1 == n)
    return res + left[0];
  try1 = press(res + left[1]);
  if(try1 == n)
    return res + left[1];
  return res + left[2];
}

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