Submission #574555

#	Time	Username	Problem	Language	Result	Execution time	Memory
574555		KrisjanisP	Combo (IOI18_combo)	C++14	97 / 100	35 ms	688 KiB

combo

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

using namespace std;
typedef long long ll;

string guess_sequence(int N) {
  string res = "";
  if(press("AB")>=1)
  {
    if(press("A")==1) res="A";
    else res="B";
  }
  else
  {
    if(press("X")==1) res="X";
    else res="Y";
  }
  if(N==1) return res;
  char a[4] = {'A','B','X','Y'};

  for(ll i=1;i<N-1;i++)
  {
    string query = "";
    char f, s;
    for(ll j=0;j<4;j++)
    {
      if(a[j]==res[0]) continue;
      query += res;
      query += a[j];
      f = a[j];
      break;
    }
    for(ll j=0;j<4;j++)
    {
      if(a[j]==res[0]||a[j]==f) continue;
      for(ll k=0;k<4;k++)
      {
        if(a[k]==res[0]) continue;
        query+=res;
        query+=a[j];
        query+=a[k];
      }
      s = a[j];
      break;
    }
    ll w = press(query);
    if(w==(ll)res.size())
    {
      for(ll j=0;j<4;j++)
      {
        if(a[j]==res[0]||a[j]==f||a[j]==s) continue;
        res += a[j];
        break;
      }
    }
    else if(w==(ll)res.size()+1)
    {
      res += f;
    }
    else if(w==(ll)res.size()+2)
    {
      res += s;
    }
  }
  
  bool found = false;
  for(ll i=0;i<3;i++)
  {
    if(a[i]==res[0]) continue;
    ll w = press(res+a[i]);
    if(w!=N) continue;
    found = true;
    res += a[i];
    break;
  }
  if(!found) res+=a[3];

  return res;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:52:33: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |         if(a[j]==res[0]||a[j]==f||a[j]==s) continue;
      |            ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~

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