Fixed isort build err

Author: liuxinyu95

sorting/insertion-sort/img/Makefile

@@ -4,6 +4,7 @@ DOT_SOURCES = $(foreach file, $(DOT_OBJECTS), $(file).dot)
 
 #suffix replacement, replace .dot with .png
 PNG_OBJECTS = $(DOT_SOURCES:.dot=.png)
+PS_OBJS = $(DOT_SOURCES:.dot=.ps)
 
 .SUFFIXES: .eps .jpg .png .dot .ps
 
@@ -37,5 +38,4 @@ png: $(PNG_OBJECTS)
 	dot -Tpng -o $@ $<
 
 clean:
-	rm -f *.ps *.eps trie-en* *~
-	rm -f $(PNG_OBJECTS)
+	rm -f $(PNG_OBJECTS) $(PS_OBJS)

sorting/insertion-sort/img/in-place-sort.dot

@@ -1,6 +1,6 @@
 digraph G{
     margin=0;
-	node[shape=record]
+	node[shape=box]
 	sorted[label=" ... sorted elements ..."];
 	x;
 	unsorted[label=" ... unsorted elements ..."];

sorting/insertion-sort/isort-en.tex

@@ -403,7 +403,7 @@ \section{Improvement 2}
     \State $L \gets $ \Call{Next}{$L$}
   \EndWhile
   \State \Call{Next}{$x$} $\gets L$
-  \If{$p \eq$ NIL}
+  \If{$p =$ NIL}
     \State $H \gets x$
   \Else
     \State \Call{Next}{$p$} $\gets x$