Submission #281661

#	Time	Username	Problem	Language	Result	Execution time	Memory
281661		MrDomino	Combo (IOI18_combo)	C++14	30 / 100	47 ms	584 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 - (int) sol.size()) + sol + b);
    if (ret == (int) sol.size()) {
      sol += c;
      continue;
    }
    if (ret > (int) sol.size() + 1) {
      sol = sol + mult(a, ret - (int) sol.size());
      continue;
    }
    if (ret == (int) sol.size() + 1) {
      if ((int) sol.size() == n - 1) {
        ret = press(sol + a);
        if (ret == n) {
          sol += a;
          continue;
        } else {
          sol += b;
          continue;
        }
      }
      /// + ab
      /// + ac
      /// + b
      ret = press(sol + a + b);
      if (ret == (int) sol.size() + 2) {
        sol += a;
        sol += b;
        continue;
      }
      if (ret == (int) sol.size() + 1) {
        sol += a;
        sol += c;
        continue;
      }
      sol += b;
      continue;
    }
  }
  return sol;
}

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