--- a/progs/catastrophic9.java Mon Jul 27 01:55:05 2020 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,48 +0,0 @@
-// A case of catastrophic backtracking in Java 9+
-//------------------------------------------------
-//
-// It is actually not too bad in comparison what Python
-// and Java 8 are to compute. But it is still pretty
-// bad, even in Java 9, considering that the the basic
-// part of the CW improves on this by a factor of 100
-// (...if implemented correctly).
-//
-// regexp: (a*)*b
-// strings: aa....aaa
-//
-// compile with: javac catastrophic9.java
-// call with: java catastrophic9
-//
-//
-
-import java.util.regex.*;
-
-public class catastrophic9 {
- public static void main(String[] args) {
-
- //we always run all the tests twice -> to warmup of the JVM
- for (int runs = 0; runs < 2; runs++) {
-
- Pattern pattern = Pattern.compile("(a*)*b");
-
- // Run from 0 to 50000 characters
- for (int length = 0; length < 50000; length += 5000) {
-
- // Build input of specified length
- String input = "";
- for (int i = 0; i < length; i++) { input += "a"; }
-
- // Measure the average duration of two calls...
- long start = System.nanoTime();
- for (int i = 0; i < 2; i++) {
- pattern.matcher(input).find();
- }
-
- // Print out time
- System.out.println(length + " a's : "
- + ((System.nanoTime() - start) / 2000000000d)
- + " secs");
- }
- }
- }
-}