#include "combo.h"
#include <bits/stdc++.h>
#define fr first
#define sc second
#define pii pair<int, int>
#define szof(s) (int)s.size()
#define all(s) s.begin(), s.end()
using namespace std;
string guess_sequence(int n) {
string bad;
string s;
if (press("A") == 1) {
s = "A";
}
else if (press("B") == 1) {
s = "B";
}
else if (press("X") == 1) {
s = "X";
}
else {
s = "Y";
}
bad = s;
if (n == 1) {
return s;
}
for (int i = 1; i <= n - 2; i++) { // we guess i + 1 character
int cost;
if (bad == "A") { // {B X Y}
cost = press(s + "B" + s + "XY" + s + "XX" + s + "XB");
if (cost == szof(s)) {
s += 'Y';
}
if (cost == szof(s) + 1) {
s += 'B';
}
if (cost == szof(s) + 2) {
s += 'X';
}
}
if (bad == "B") { // {A X Y}
cost = press(s + "A" + s + "XY" + s + "XX" + s + "XA");
if (cost == szof(s)) {
s += 'Y';
}
if (cost == szof(s) + 1) {
s += 'A';
}
if (cost == szof(s) + 2) {
s += 'X';
}
}
if (bad == "X") { // { A B Y }
cost = press(s + "A" + s + "BA" + s + "BB" + s + "BY");
if (cost == szof(s)) {
s += 'Y';
}
if (cost == szof(s) + 1) {
s += 'A';
}
if (cost == szof(s) + 2) {
s += 'B';
}
}
if (bad == "Y") { // { A B X }
cost = press(s + "A" + s + "BA" + s + "BB" + s + "BX");
if (cost == szof(s)) {
s += 'X';
}
if (cost == szof(s) + 1) {
s += 'A';
}
if (cost == szof(s) + 2) {
s += 'B';
}
}
}
// we don't need ask bad char
vector <string> good = {};
if (bad != "A") {
good.push_back("A");
}
if (bad != "B") {
good.push_back("B");
}
if (bad != "X") {
good.push_back("X");
}
if (bad != "Y") {
good.push_back("Y");
}
for (auto to : good) {
if (press(s + to) == n) {
s += to;
}
}
return s;
}
