--- a/cws/cw04.tex	Thu Jan 17 00:53:24 2019 +0000
+++ b/cws/cw04.tex	Mon Jan 21 16:04:30 2019 +0000
@@ -1,3 +1,4 @@
+% !TEX program = xelatex
 \documentclass{article}
 \usepackage{../style}
 \usepackage{../langs}
@@ -103,7 +104,7 @@
 expressions. The background is that ``out-of-the-box'' regular
 expression matching in mainstream languages like Java, JavaScript and
 Python can sometimes be excruciatingly slow. You are supposed to implement
-an regular expression macther that is much, much faster. The advanced part is
+an regular expression matcher that is much, much faster. The advanced part is
 about the shunting yard algorithm that transforms the usual infix
 notation of arithmetic expressions into the postfix notation, which is
 for example used in compilers.\bigskip
@@ -112,7 +113,7 @@
 
 \noindent
 Also note that the running time of each part will be restricted to a
-maximum of 30 seconds on my laptop.
+maximum of 30 seconds on my laptop.  
 
 \DISCLAIMER{}