Submission #867743

#	Time	Username	Problem	Language	Result	Execution time	Memory
867743		ElenaBM	Combo (IOI18_combo)	C++17	Compilation error	0 ms	0 KiB

combo

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

using namespace std;

string guess_sequence (int N){
    vector<char>sec(3);
    string ans = '';
    if (press("AB") > 0){
        if (press("A")) {
            ans += 'A';
            sec[0] = 'B';
        }
        else {
            ans += 'B';
            sec[0] = 'A';
        }
        sec[1] = 'X';
        sec[2] = 'Y';
    }
    else{
        sec[0] = 'A';
        sec[1] = 'B';
        if (press("X")) {
            ans += 'X';
            sec[2] = 'Y';
        }
        else {
            ans += 'Y';
        }
    }
    for (int i = 2; i <= N; ++i){
        string guess = ans + sec[0] + ans + sec[1] + sec[0] + ans + sec[1] + sec[1] + ans + sec[1] + sec[2];
        int x = press(guess);
        if (x == i) ans += sec[0];
        else if (x == i+1) ans += sec[1];
        else ans += sec[2];
    }
    return ans;
}

Compilation message (stderr)

combo.cpp:8:18: error: empty character constant
    8 |     string ans = '';
      |                  ^~
combo.cpp: In function 'std::string guess_sequence(int)':
combo.cpp:8:18: error: conversion from 'char' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested