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\title{Foundations of Information Systems}
\author{Winter Semester 2026--27, Exercise 4}
\date{For discussion on Wednesday, November 11, 2026}
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\begin{enumerate}

\item Describe an algorithm which takes a string containing upper and
lower case characters encoded in ASCII and outputs the same string in
all lower case. (For simplicity, assume that your input string does
not contain any symbols other than characters of the Latin alphabet.
You may describe your algorithm in pseudo-code or in Python.)

\item How many characters can we encode with a mixed 8/16 bit
representation if we insist that an 8 bit character always has 0 in
the first bit, and a 16 bit character always has 1 in the first bit of
each of its bytes?

\item List at least three advantages of the UTF-8 encoding over the
UTF-16 encoding of Unicode characters.

\item Describe an algorithm that checks whether a UTF-8 encoded string
contains any characters that are not part of the ASCII character set.

\end{enumerate}
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