Consider two unknown binary strings $$X = x_{1} x_{2} \dots x_{n^{2}}, \quad Y = y_{1} y_{2} \dots y_{n^{2}}, \quad x_{i}, y_{i} \in \{0, 1\} .$$ We may request a string $Z = z_{1} z_{2} \dots z_{n^{2}}$, where $z_{i} = x_{i}$ or $z_{i} = y_{i}$, no more than $n + 1$ times. So, for every request we set required $z_{i}$ (that is, $x_{i}$ or $y_{i}$) for every $i$.
Moreover, we have $n$ bits of unwritable memory, namely, every bit of that memory is set once and then does not change. This memory is avaliable all the time, but requested $Z$ strings drop out before the next request, so, we don't have complete list of all requested $Z$ strings.
The problem is to check if $X = Y$ with given $n$ bits and $n + 1$ times for $Z$ string request.
There is an extra question: is it possible to use $\mathcal{O}(\log^{2}(n))$ bits of memory and $\mathcal{O}(\log(r))$ requests.
I don't really understand area of CS that is closely related to the problem, could anyone give a hint?
