Submission #281682

#	Time	Username	Problem	Language	Result	Execution time	Memory
281682		MrDomino	Combo (IOI18_combo)	C++14	30 / 100	78 ms	656 KiB

combo

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

using namespace std;

string del(string s, char ch) {
  string t;
  for (auto &x : s) {
    if (x != ch) {
      t += x;
    }
  }
  return t;
}

mt19937 rng((long long) (new char));

string mult(char ch, int x) {
  string s;
  for (int i = 1; i <= x; i++) {
    s += ch;
  }
  return s;
}

string guess_sequence(int n) {
  string sol;
  string posi = "ABXY";
  bool found = 0;
  for (int j = 0; j < 3; j++) {
    if (press(sol + posi[j]) == 1) {
      found = 1;
      sol += posi[j];
      break;
    }
  }
  if (found == 0) {
    sol += posi[3];
  }
  posi = del(posi, sol[0]);
  while ((int) sol.size() + 1 <= n) {
    shuffle(posi.begin(), posi.end(), rng);
    char a = posi[0];
    char b = posi[1];
    char c = posi[2];
    int ret = press(sol + mult(a, n) + sol + mult(b, n));
    if (ret == (int) sol.size()) {
      sol += c;
      continue;
    }
    if (ret == n) {
      if (press(sol + mult(a, n)) == n) {
        sol += mult(a, n - (int) sol.size());
      } else {
        sol += mult(b, n - (int) sol.size());
      }
      continue;
    }
    /// aaaaaaaab
    /// aaaaaaaac
    /// bbbbbbbba
    /// bbbbbbbbc
    int ret2 = press(sol + mult(a, ret - (int) sol.size()) + mult(b, n));
    if (ret2 > ret) {
      sol += mult(a, ret - (int) sol.size()) + mult(b, ret2 - ret);
      continue;
    }
    if (ret2 == ret) {
      sol += mult(a, ret - (int) sol.size()) + c;
      continue;
    }
    int ret3 = press(sol + mult(b, ret - (int) sol.size()) + mult(a, n));
    if (ret3 > ret2) {
      sol += mult(b, ret - (int) sol.size()) + mult(a, ret3 - ret);
    } else {
      sol += mult(b, ret - (int) sol.size()) + c;
    }
  }
  return sol;
}

• Subtask 1: 5 / 5
• Subtask 2: 25 / 95