Submission #587977

#	Time	Username	Problem	Language	Result	Execution time	Memory
587977		vilji	Combo (IOI18_combo)	C++17	97 / 100	33 ms	528 KiB

combo

#include <bits/stdc++.h>

#define rep(i, a, b) for (int i = (a); i < (b); i++)

using namespace std;

#define pb push_back

#include "combo.h"

string guess_sequence(int N) {
  vector<char> btns = {'A', 'B', 'X', 'Y'};
  char fst;
  rep(i, 0, btns.size()) {
    int c = btns[i];
    if (i == 3) {
      fst = c;
      break;
    }
    string p = "";
    p += c;
    int coins = press(p);
    if (coins != 0) {
      fst = c;
      break;
    }
  }

  vector<char> oth;

  if (N == 1) {
    string res = "";
    res += fst;
    return res;
  }

  for (char c : btns) {
    if (c != fst) oth.pb(c);
  }

  string ans = "";
  ans += fst;

  rep(i, 1, N - 1) {
    string p = "";
    p += ans;
    p += oth[0];
    p += oth[0];
    p += ans;
    p += oth[0];
    p += oth[1];
    p += ans;
    p += oth[0];
    p += oth[2];
    p += ans;
    p += oth[1];
    int coins = press(p);

    if (coins == i)
      ans += oth[2];
    else if (coins == i + 1)
      ans += oth[1];
    else if (coins == i + 2)
      ans += oth[0];
    else
      assert(false);
  }

  for (int i = 0; i < 3; i++) {
    char c = oth[i];
    if (i == 2) {
      string p = ans;
      p += c;
      return p;
    }
    string p = ans;
    p += c;
    int coins = press(p);
    if (coins == N) {
      return p;
    }
  }

  assert(false);
  return "";
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:3:42: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    3 | #define rep(i, a, b) for (int i = (a); i < (b); i++)
      |                                          ^
combo.cpp:14:3: note: in expansion of macro 'rep'
   14 |   rep(i, 0, btns.size()) {
      |   ^~~

• Subtask 1: 5 / 5
• Subtask 2: 92 / 95