Submission #554182

#	Time	Username	Problem	Language	Result	Execution time	Memory
554182		d4xn	콤보 (IOI18_combo)	C++17	0 / 100	1 ms	304 KiB

combo

#include "combo.h"

#pragma GCC optimize ("Ofast")
#include <bits/stdc++.h>
using namespace std;

#define pb push_back

string guess_sequence(int N) {
  string p;

  vector<char> f = {'A', 'B', 'X', 'Y'};

  for (int j = 0; j < 4; j++) {
    int k = j + rand() % (4 - j);
    swap(f[j], f[k]);
  }

  int idx = 0;
  for (int i = 0; i < 3; i++) {
    p.pb(f[i]);

    if (i > 0) {
      for (int j = 1; j < N; j++) {
        char x = f[rand() % i];
        p.pb(x);
      }
    }

    idx = press(p);
    if (idx) break;

    p.clear();
  }

  bool iKnowCurr = idx > 0;

  if (!idx) {
    p.pb(f[3]);
    for (int i = 1; i < N; i++) {
      char x = f[rand() % 3];
      p.pb(x);
    }
  }
  /*
  else {
    for (int i = 1; i < N; i++) {
      char x = f[rand() % 4];
      while (x == p[0]) {
        x = f[rand() % 4];
      }
      p[i] = x;
    }
  }
  */
  
  vector<char> v;
  for (char i : {'A', 'B', 'X', 'Y'}) {
    if (p[0] == i) continue;
    v.pb(i);
  }

  for (int j = 0; j < 3; j++) {
    int k = j + rand() % (3 - j);
    swap(v[j], v[k]);
  }

  idx = max(idx, 1);
  while (idx < N) {
    if (iKnowCurr) {
      char x, y;
      x = y = 'a';
      for (int i = 0; i < 3; i++) {
        if (p[idx] == v[i]) continue;
        if (x == 'a') x = v[i];
        else y = v[i];
      }

      p[idx] = x;
      int newIdx = press(p);

      if (newIdx > idx) {
        idx = newIdx;
        iKnowCurr = 1;
        continue;
      }
        
      p[idx] = y;
      iKnowCurr = 0;
      idx++;
    }
    else {
      char x, y, z;
      x = v[0];
      y = v[1];
      z = v[2];

      p[idx] = x;
      int newIdx = press(p);

      if (newIdx > idx) {
        idx = newIdx;
        iKnowCurr = 1;
        continue;
      }

      p[idx] = y;
      newIdx = press(p);

      if (newIdx > idx) {
        idx = newIdx;
        iKnowCurr = 1;
        continue;
      }

      p[idx] = z;
      iKnowCurr = 0;
      idx++;
    }
  }

  cerr << p << endl;
  return p;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 95