Submission #757766

#	Time	Username	Problem	Language	Result	Execution time	Memory
757766		taher	Combo (IOI18_combo)	C++17	100 / 100	32 ms	660 KiB

combo

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

using namespace std;

/*
int press(string s) {
  cout << s << '\n';
  cout.flush();
  int val;
  cin >> val;
  return val;
}
*/

string Guess_first() {
  if (press("AB")) {
    if (press("A")) return "A";
    return "B";
  }
  else {
    if (press("X")) return "X";
    return "Y";
  }
}

bool Guess_last(string f) {
  int n = (int)f.length();
  if (press(f) == n) {
    return true;
  }
  return false;
}

string guess_sequence(int n) {
  string s = Guess_first();
  string ans = s;
  string c = "ABXY";
  for (int i = 0 ; i < 4 ; i++) {
    if (c[i] == s[0]) {
      c.erase(c.begin() + i);
      break;
    }
  }
  auto Create = [&](string cur) {
    cur += c[0];
    cur += s;
    cur += c[1]; 
    cur += c[0];
    cur += s;
    cur += c[1]; 
    cur += c[1];
    cur += s;
    cur += c[1];
    cur += c[2];
    assert((int)cur.length() <= 4 * n);
    return cur;
  };
  for (int i = 1 ; i < n - 1 ; i += 1) {
    string cur = Create(ans);
    int foo = press(cur);
    if (foo == i) {
      ans += c[2];
    }
    else if (foo == i + 1) {
      ans += c[0];
    }
    else {
      ans += c[1];
    }
    s = ans;
  }
  if (n > 1) {
    bool ok = false;
    for (int i = 0 ; i < 2 ; i++) {
      string cur = ans + c[i];    
      if (Guess_last(cur)) {
        ok = true;
        ans += c[i];
        break;
      }
    }
    if (!ok) {
      ans += c[2];
    }
  }
  return ans;
}


/*
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  string ans = guess_sequence(n);
  cout << ans << '\n';
  return 0; 
}
 */

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