Submission #875048

#	Time	Username	Problem	Language	Result	Execution time	Memory
875048		amin_2008	Combo (IOI18_combo)	C++17	100 / 100	13 ms	1844 KiB

combo

#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
#define REP(i,n) for(int i=0;i<(n);++i)


const int M = 4;
const char LET[] = "ABXY";
int guess_one(const string& s) {
  int len = press(s + LET[0] + s + LET[1]);
  int idx = 2*(len < s.length()+1);
  len = press(s + LET[idx]);
  idx += (len < s.length()+1);
  return idx;
}
string guess_sequence(int N) {
  int idx[M];
  REP(i, M) { idx[i] = i; }
  string s;
  {
    int id = guess_one(s);
    s += LET[id];
    swap(idx[id], idx[M-1]);
  }
  REP(i, N-2) {
    string z;
    REP(j, M-1) {
      z += s + LET[idx[0]] + LET[idx[j]];
    }
    z += s + LET[idx[1]];
    int len = press(z);
    if (len == i+3) {
      s += LET[idx[0]];
    } else if (len == i+2) {
      s += LET[idx[1]];
    } else {
      s += LET[idx[2]];
    }
  }
  if (N > 1) {
    int id = guess_one(s);
    s += LET[id];
  }

  return s;
}

Compilation message (stderr)

combo.cpp: In function 'int guess_one(const string&)':
combo.cpp:11:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |   int idx = 2*(len < s.length()+1);
      |                ~~~~^~~~~~~~~~~~~~
combo.cpp:13:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |   idx += (len < s.length()+1);
      |           ~~~~^~~~~~~~~~~~~~

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