#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
string guess_sequence(int N){
string S = "";
int first = 5, last = 1;
//bool a;
char buttons[4] = {'A', 'B', 'X', 'Y'};
vector<char> b; // size of b = 3
for(int i = 0; i < 3; i++){
if(press(S + buttons[i]) == 1){
first = i;
S += buttons[i];
break;
}
}
if(first == 5){
first = 3;
S += buttons[3];
}
// Q = 3 at worst
for(int i = 0; i < 4; i++){
if(i != first){
b.push_back(buttons[i]); // New button list
}
}
/*for(int i = 1; i < N; i++){
a = false;
for(int j = 0; j < 2; j++){
if(press(S + b[j]) == i + 1){
S += b[j];
a = true;
break;
}
}
if(a == false){
S += b[2];
}
}*/
// Q = 2*N + 1 at worst (25 points)
int prefix;
for(int i = 1; i < N; i++){
//a = false;
prefix = press(S + b[0]);
S += b[0];
if(prefix == i + 1){
last = i + 1;
}
else{
last = prefix;
if(S[last] == b[0]){
S[last] = b[1];
}
else{
S[last] = b[2];
}
}
}
prefix = press(S);
while(prefix != N){
last = prefix;
if(S[last] == b[0]){
S[last] = b[1];
}
else{
S[last] = b[2];
}
prefix = press(S);
}
return S;
}
