#include "combo.h"
#include <algorithm>
#include <string>
std::string guess_sequence(int N) {
std::string cur;
for (const char c: "ABXY") {
if (press(cur = c)) break;
}
std::string poss = "ABXY"; poss.erase(poss.find(cur[0]), 1);
const char A = poss[0], B = poss[1], X = poss[2];
while ((int) cur.size()+2 <= N) {
// Let s = cur, A,B,X = poss
// Try sAA + sAB + sBA
int p = press(cur+A+A + cur+A+B + cur+B+A);
const int sz = cur.size();
if (p == sz) {
// Next char is X
cur += X;
}
else if (p == sz+1) {
// Next chars are AX,BB,BX
p = press(cur+B+B);
if (p == sz+2) cur += B, cur += B;
else if (p == sz+1) cur += B, cur += X;
else cur += A, cur += X;
}
else {
// Next chars are AA,AB,BA
p = press(cur+A+A);
if (p == sz+2) cur += A, cur += A;
else if (p == sz+1) cur += A, cur += B;
else cur += B, cur += A;
}
}
if (N == (int) cur.size()) return cur;
if (press(cur+A) == N) return cur+A;
else if (press(cur+B) == N) return cur+B;
else return cur+X;
}
