#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
string guess_sequence(int N) {
string ret = "";
ret += '.';
char ch[4] = {'A', 'B', 'X', 'Y'};
int firstChar = 'A';
for (int i = 1; i < 4; i++) {
ret.back() = ch[i];
int len = press(ret);
if (len == 1) {
firstChar = ch[i];
break;
}
}
ret.back() = firstChar;
vector <char> options;
for (int i = 0; i < 4; i++) {
if (ch[i] != firstChar) {
options.push_back(ch[i]);
}
}
for (int i = 2; i <= N; i++) {
ret += '.';
char nextChar = options.back();
for (int j = 0; j <= 1; j++) {
ret.back() = options[j];
int len = press(ret);
if (len == i) {
nextChar = options[j];
break;
}
}
ret.back() = nextChar;
}
return ret;
}
