# Hidden path in square grids

I stumbled on an open problem posed by David Eppstein and I am interested in its complexity status. He conjectured that it is NP-complete.

Input: $n$ by $n$ matrix of 0’s and 1’s, sequence of $n^2$ 0’s and 1’s

Question: Is there a path through adjacent matrix entries, covering each matrix entry exactly once, with values matching the given sequence?

Did anyone prove that the problem is indeed hard?

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