[ps1] add alternative solution for ps3

1 files changed, 8 insertions, 0 deletions

diff --git a/ps1/main.tex b/ps1/main.tex
index 65c7707..920cb3c 100644
--- a/ps1/main.tex
+++ b/ps1/main.tex
@@ -152,6 +152,14 @@ t = w}
 
 \section*{Problem 3}
 
+\paragraph{First solution \emph{(too easy, feels like cheating).}} We saw in
+class how to compute the most signigicant bit set to one. But observe that
+\texttt{x \& $\sim$(x-1)} will clear all the bits of $x$ except for the least
+significant bit set to one.  Assuming access to a procedure \texttt{msb} to
+compute the most significant bit set to one, we can simply define
+\texttt{lsb(x) $:=$ msb(x \& $\sim$(x-1))}.
+
+\paragraph{Second solution.}
 Using Problem 2 and what we did in class, we assume that we have access to the
 following procedures:
 \begin{itemize*}