Merge pull request #69 from BlackTea1988/master

fix bug

chapters/strings/matching-strings.md

@@ -1,45 +1,42 @@
----
-layout:   recipe
-title:    Matching Strings
-chapter:  Strings
----
-## Problem
-
-You want to match two or more strings.
-
-## Solution
-
-Calculate the edit distance, or number of operations required to transform one string into the other.
-
-{% highlight coffeescript %}
-
-Levenshtein =
-  (str1, str2) ->
-
-    l1 = str1.length
-    l2 = str2.length
-
-    Math.max l1, l2 if Math.min l1, l2 == 0      
-
-    i = 0; j = 0; distance = []
-
-    for i in [0...l1 + 1]
-     distance[i] = []
-     distance[i][0] = i
-
-    distance[0][j] = j for j in [0...l2 + 1]
-
-    for i in [1...l1 + 1]
-     for j in [1...l2 + 1]
-       distance[i][j] = Math.min distance[i - 1][j] + 1,
-         distance[i][j - 1] + 1,                         
-         distance[i - 1][j - 1] + 
-           if (str1.charAt i - 1) == (str2.charAt j - 1) then 0 else 1
-
-    distance[l1][l2]
-
-{% endhighlight %}
-
-## Discussion
-
-You can use either Hirschberg or Wagner–Fischer's algorithm to calculate a Levenshtein distance. This example uses Wagner–Fischer's algorithm.
+---
+layout:   recipe
+title:    Matching Strings
+chapter:  Strings
+---
+## Problem
+
+You want to match two or more strings.
+
+## Solution
+
+Calculate the edit distance, or number of operations required to transform one string into the other.
+
+{% highlight coffeescript %}
+
+Levenshtein =
+  (str1, str2) ->
+
+    l1 = str1.length
+    l2 = str2.length
+
+    return Math.max l1, l2 unless l1 and l2
+
+    i = 0; j = 0; distance = []
+
+    distance[i] = [i] for i in [0..l1]
+    distance[0][j] = j for j in [0..l2]
+
+    for i in [1..l1]
+     for j in [1..l2]
+       distance[i][j] = Math.min distance[i - 1][j] + 1,
+         distance[i][j - 1] + 1,                         
+         distance[i - 1][j - 1] + 
+           if (str1.charAt i - 1) is (str2.charAt j - 1) then 0 else 1
+
+    distance[l1][l2]
+
+{% endhighlight %}
+
+## Discussion
+
+You can use either Hirschberg or Wagner–Fischer's algorithm to calculate a Levenshtein distance. This example uses Wagner–Fischer's algorithm.