Submission #815210

#	Time	Username	Problem	Language	Result	Execution time	Memory
815210		erray	Combo (IOI18_combo)	C++17	100 / 100	43 ms	644 KiB

combo

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

using namespace std;
 
#ifdef DEBUG
  #include "/home/ioi/codes/debug.h"
#else
  #define debug(...) (void) 37
#endif


string M = "ABXY";
std::string guess_sequence(int N) {
  int p = 2 * (press(string(2 * N, M[0]) + string(2 * N, M[1])) == 0);
  p += press(string(4 * N, M[p + 1]));
  char first = M[p];
  string ans = ""s + M[p];  
  M.erase(find(M.begin(), M.end(), M[p]));
  for (int i = 1; i < N - 1; ++i) {
    string ask;
    ask += ans + M[1];
    for (int c = 0; c < 3; ++c) {
      ask += ans + M[2] + M[c];
    }
    ask += string(4 * N - int(ask.size()), first);
    ans += M[press(ask) - i];
  }
  if (N > 1) {
    char last = M[2];
    for (int i = 0; i < 2; ++i) {
      string ask = ans + M[i];
      if (press(ask + ask + ask + ask) == N) {
        last = M[i];
      }
    }
    ans += last;  
  }
  return ans;
}

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