#include "combo.h"
#include <vector>
using namespace std;
vector<char> c = {'A', 'B', 'X', 'Y'};
string guess_sequence(int N){
string ans = "", q;
int l = 0, r = 3;
while (l != r){
int mid = (l + r) / 2;
q = "";
for (int i = l; i <= mid; i++){
q += c[i];
}
if (press(q) == 0){
l = mid + 1;
}
else{
r = mid;
}
}
vector<char> al;
for (int i = 0; i < 4; i++){
if (l != i){
al.push_back(c[i]);
}
}
ans += c[l];
if (N == 1) return ans;
for (int i = 0; i < N - 2; i++){
q = ans + al[0] + ans + al[1] + al[0] + ans + al[1] + al[1] + ans + al[1] + al[2];
int res = press(q);
if (res == i + 1){
ans += al[2];
}
else if (res == i + 2){
ans += al[0];
}
else{
ans += al[1];
}
}
if (press(ans + al[0]) == N) return ans + al[0];
if (press(ans + al[1]) == N) return ans + al[1];
return ans + al[2];
}
