#include "combo.h"
#include <bits/stdc++.h>
using namespace std;
std::string guess_sequence(int N) {
std::string s = "";
string ref = "ABXY";
int n = N;
// brute force first char
int abguess = press("AB");
if(abguess > 0){
if(press("B") == 1) s += 'B';
else s += 'A';
}
else{
if(press("X") == 1) s += 'X';
else s += 'Y';
}
if(n == 1) return s;
// only need to guess three other chars
string p = "";
for(auto e : ref) if(e != s[0]) p += e;
for(int i = 1; i < n - 1; i++){
string guess =
s + p[0] +
s + p[1] + p[0] +
s + p[1] + p[1] +
s + p[1] + p[2];
int coins = press(guess);
int gain = coins - i;
if(gain == 0){
s += p[2];
}
if(gain == 1){
s += p[0];
}
if(gain == 2){
s += p[1];
}
}
for(int i = 0; i < 2; i++){
int coin = press(s + p[i]);
if(coin == n){
s += p[i];
break;
}
}
if(s.size() != n) s += p[2];
return s;
}
