Advanced handouts

Add missing file
Co-authored-by: Mark <mark@betalupi.com>
Co-committed-by: Mark <mark@betalupi.com>

src/Advanced/De Bruijn/parts/0 intro.tex

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+\section{Introduction}
+
+\example{}<lockproblem>
+A certain electronic lock has two buttons: \texttt{0} and \texttt{1}.
+It opens as soon as the correct two-digit code is entered, completely ignoring
+previous inputs. For example, if the correct code is \text{10}, the lock will open
+once the sequence \texttt{010} is entered.
+
+\vspace{2mm}
+
+Naturally, there are $2^2 = 4$ possible combinations that open this lock. \par
+If we don't know the lock's combination, we could try to guess it by trying all four combinations. \par
+This would require eight key presses: \texttt{0001101100}.
+
+\problem{}
+There is, of course, a better way. \par
+Unlock this lock with only 5 keypresses.
+
+\begin{solution}
+	The sequence \texttt{00110} is guaranteed to unlock this lock.
+\end{solution}
+\vfill
+
+Now, consider the same lock, now set with a three-digit binary code.
+\problem{}
+How many codes are possible?
+\vfill
+
+\problem{}
+Show that there is no solution with fewer than three keypresses
+\vfill
+
+\problem{}
+What is the shortest sequence that is guaranteed to unlock the lock? \par
+\hint{You'll need 10 digits.}
+
+\begin{solution}
+	\texttt{0001110100} will do.
+\end{solution}
+
+
+%\problem{}
+%How about a four-digit code? How many digits do we need? \par
+%
+%\begin{instructornote}
+%	Don't spend too much time here.
+%	Provide a solution at the board once everyone has had a few
+%	minutes to think about this problem.
+%\end{instructornote}
+%
+%\begin{solution}
+%	One example is \texttt{0000 1111 0110 0101 000}
+%\end{solution}
+
+\vfill
+\pagebreak