--- a/cws/cw02.tex Tue Nov 14 13:14:47 2017 +0000
+++ b/cws/cw02.tex Tue Nov 14 21:34:22 2017 +0000
@@ -188,7 +188,7 @@
\noindent
Let us first fix the basic datastructures for the implementation. The
board dimension is an integer (we will never go beyond board sizes of
-$50 \times 50$). A \emph{position} (or field) on the chessboard is
+$40 \times 40$). A \emph{position} (or field) on the chessboard is
a pair of integers, like $(0, 0)$. A \emph{path} is a list of
positions. The first (or 0th move) in a path is the last element in
this list; and the last move in the path is the first element. For
@@ -219,7 +219,7 @@
\item[(1b)] Implement a \texttt{legal-moves} function that calculates for a
position all legal onward moves. If the onward moves are
placed on a circle, you should produce them starting from
- ``12-oclock'' following in clockwise order. For example on an
+ ``12-o'clock'' following in clockwise order. For example on an
$8\times 8$ board for a knight on position $(2, 2)$ and otherwise
empty board, the legal-moves function should produce the onward
positions in this order:
@@ -292,14 +292,14 @@
\textbf{Testing} The first tour function will be called with board
sizes of up to $8 \times 8$.
-
+%%\newpage
\subsection*{Part 2 (3 Marks)}
-As you should have seen in Part 1, a naive search for tours
-beyond $8 \times 8$ boards and also searching for closed tours
-takes too much time. There is a heuristic, called Warnsdorf's rule
-that can speed up finding a tour. This heuristic states that a knight
-is moved so that it always proceeds to the field from which the
+As you should have seen in Part 1, a naive search for tours beyond
+$8 \times 8$ boards and also searching for closed tours even on small
+boards takes too much time. There is a heuristic, called Warnsdorf's
+rule that can speed up finding a tour. This heuristic states that a
+knight is moved so that it always proceeds to the field from which the
knight will have the \underline{fewest} onward moves. For example for
a knight on field $(1, 3)$, the field $(0, 1)$ has the fewest possible
onward moves, namely 2.
@@ -342,10 +342,12 @@
a solution when started in the middle of the board (that is
position $(dimension / 2, dimension / 2)$). \hfill[1 Mark]
-\item[(3c)] Implement a first-tour-heuristic function for boards up to $50\times 50$.
- It is the same function as in (3b) but searches for tours. You have
- to be careful to write a tail-recursive version of the first-tour-heuristic
- function otherwise you will get problems with stack-overflows. \hfill[1 Mark]
+\item[(3c)] Implement a first-tour-heuristic function for boards up to
+ $40\times 40$. It is the same function as in (3b) but searches for
+ tours (not just closed tours). You have to be careful to write a
+ tail-recursive version of the first-tour-heuristic function
+ otherwise you will get problems with stack-overflows.\\
+ \mbox{}\hfill[1 Mark]
\end{itemize}
\end{document}