#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
vector<char> letters = {'A', 'B', 'X', 'Y'};
string guess_sequence(int N) {
string p = "";
int coins;
if (N == 1) {
for (int i = 0; i < (int) letters.size() - 1; i++) {
if ((coins = press(p + letters[i])) > 0) {
p += letters[i];
break;
}
}
if ((int) p.size() == 0) {
p += letters[letters.size() - 1];
}
return p;
}
// Find first character
coins = press("AB");
if (coins > 0) {
if ((coins = press("A")) > 0) {
p += 'A';
letters.erase(letters.begin() + 0);
}
else {
p += 'B';
letters.erase(letters.begin() + 1);
}
}
else {
if ((coins = press("X")) > 0) {
p += 'X';
letters.erase(letters.begin() + 2);
}
else {
p += 'Y';
letters.erase(letters.begin() + 3);
}
}
// Find characters 2...N-1
string guess;
for (int i = 2; i <= N - 1; i++) {
guess = p + letters[0] + p + letters[1] + letters[0] + p + letters[1] + letters[1] + p + letters[1] + letters[2];
coins = press(guess) - p.size();
switch (coins) {
case 0:
p += letters[2];
break;
case 1:
p += letters[0];
break;
case 2:
p += letters[1];
break;
}
}
// Find last character
for (int i = 0; i < (int) letters.size() - 1; i++) {
if ((coins = press(p + letters[i])) == N) {
p += letters[i];
letters.erase(letters.begin() + i);
break;
}
}
if ((int) p.size() == N - 1) {
p += letters[letters.size() - 1];
}
string S = p;
return S;
}
