Qgram.similarity = 0 if string.length < n

NGram : completed main example

Author: tdebatty

src/info/debatty/java/stringsimilarity/NGram.java

@@ -17,6 +17,11 @@ public static void main(String[] args) {
         NGram twogram = new NGram(2);
 
         System.out.println(twogram.distance("ABCD", "ABTUIO"));
+        
+        String s1 = " Buy And Download Cheap OemSoftwares! Adobe CreativeSuite 5 Master Collection from cheap 4zp";
+        String s2 = " Buy And Download Cheap OemSoftwares! Adobe CreativeSuite 5 Master Collection from cheap d1x";
+        NGram ngram = new NGram(4);
+        System.out.println(ngram.similarity(s1, s2));
     }
 
     private final int n;

src/info/debatty/java/stringsimilarity/QGram.java

@@ -35,6 +35,10 @@ public double similarity(String s1, String s2) {
 
     @Override
     public double distance(String s1, String s2) {
+        if (s1.length() < n || s2.length() < n) {
+            return 0;
+        }
+        
         KShingling sh = new KShingling(n);
         sh.parse(s1);
         sh.parse(s2);