Submission #1085405

#	Time	Username	Problem	Language	Result	Execution time	Memory
1085405		mingga	Combo (IOI18_combo)	C++17	Compilation error	0 ms	0 KiB

combo

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

using namespace std;

#define ln "\n"
#define dbg(x) cout << #x << " = " << x << ln
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define inf 2e18
#define fast_cin()                  \
  ios_base::sync_with_stdio(false); \
  cin.tie(NULL)
#define out(file) freopen(file, "w", stdout)
#define in(file) freopen(file, "r", stdin)
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
// #define int long long
int MOD = 1e9 + 7;

string d[4] = {"A", "B", "X", "Y"};

string guess_sequence(int n) {
  string ans = "";
  if(press("AB") > 0) {
    if(press("A") == 1) ans += 'A';
    else ans += 'B';
  } else {
    if(press("X") == 1) ans += 'X';
    else ans += 'Y';
  }
  string fir = ans[0];
  vector<string> vec;
  for(int i = 0; i < 4; i++) {
    if(d[i] == fir) continue;
    vec.pb(d[i]);
  }
  int st = 1;
  if((n-1) % 2 != 0) {
    st = 2;
    string tmp = ans + vec[0];
    if(press(tmp) == 2) ans += vec[0];
    else {
      tmp = ans + vec[1];
      if(press(tmp) == 2) ans += vec[1];
      else ans += vec[2]; 
    }
  }
  if(n == 3) {
    for(int i = 0; i < 3; i++) {
      for(int j = 0; j < 3; j++) {
        string tmp = ans + vec[i] + vec[j];
        if(press(tmp) == n) {
          return tmp;
        }
      }
    }
  }
  for(int i = st; i < n; i+=2) {
      string tmp = ans + vec[0] + vec[1] + ans + vec[1] + vec[0] + ans + vec[1] + vec[1] + ans + vec[0] + vec[0];
      // cout << tmp << ln;
      int cur = press(tmp);
      if(cur == sz(ans)) {
        tmp = ans + vec[2] + vec[0];
        string tmp2 = ans + vec[2] + vec[1];
        if(press(tmp) == sz(ans) + 2) ans += vec[2] + vec[0];
        else if(press(tmp2) == sz(ans) + 2) ans += vec[2] + vec[1];
        else ans += vec[2] + vec[2];
      } else if(cur == sz(ans) + 1) {
        tmp = ans + vec[1] + vec[2];
        if(press(tmp) == sz(ans) + 2) ans += vec[1] + vec[2];
        else ans += vec[0] + vec[2];
      } else {
        tmp = ans + vec[1] + vec[1];
        int sus = press(tmp);
        if(sus == sz(ans)) {
          tmp = ans + vec[0] + vec[1];
          if(press(tmp) == sz(ans) + 2) ans += vec[0] + vec[1];
          else ans += vec[0] + vec[0];
        }
        else if(sus == sz(ans) + 1) {
          ans += vec[1] + vec[0];
        } else {
          ans += vec[1] + vec[1];
        }
      }
  }
  return ans;
}

// signed main() {
//   string a = "";
//   a += d[1] + d[2] + d[0];
//   string tmp = a + d[0] + a + d[1] + a + d[2] + a + d[3];
//   cout << tmp; 
// }

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:34:21: error: conversion from '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
   34 |   string fir = ans[0];
      |                     ^