Submission #670667

#	Time	Username	Problem	Language	Result	Execution time	Memory
670667		Essa2006	Combo (IOI18_combo)	C++14	Compilation error	0 ms	0 KiB

combo

#include<bits/stdc++.h>
#include "combo.h"
using namespace std;
#define ll long long 
#define endl '\n'
#define FF first
#define SS second
#define all(a) a.begin(), a.end()
#define mod (ll)(1000000007)

string ans="";
string guess_sequence(int n){
    string a="ABXY";
    char c;
    for(int i=0;i<4;i++){
        if(press(a[i]))
            ans.push_back(a[i]), c=a[i];
    }
    string b=a;
    a="";
    for(int i=0;i<4;i++){
        if(b[i]!=c)
            a.push_back(b[i]);
    }
    for(int i=1;i<n;i++){
        for(int j=0;j<3;j++){
            if(press(ans+b[j])==i+1){
                ans.push_back(b[j]);
                break;
            }
        }
    }
    return ans;
}

Compilation message (stderr)

combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:16:22: error: could not convert 'a.std::__cxx11::basic_string<char>::operator[](((std::__cxx11::basic_string<char>::size_type)i))' from '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} to 'std::string' {aka 'std::__cxx11::basic_string<char>'}
   16 |         if(press(a[i]))
      |                      ^
      |                      |
      |                      __gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type {aka char}