1 import java.util.regex.*;

     2 

     3 public class catastrophic {

     4     public static void main(String[] args) {

     5         for (int runs = 0; runs < 2; runs++) {

     6             //Pattern pattern = Pattern.compile("(0*)*A");

     7             //Pattern pattern = Pattern.compile("a?{20}a{20}");

     8 

     9             // Run from 5 to 25 characters

    10             for (int length = 5; length < 25; length++) {

    11                 Pattern pattern = Pattern.compile("(0*)*A");

    12                 // Build input of specified length

    13                 String input = "";

    14                 for (int i = 0; i < length; i++) { input += "0"; }

    15                 

    16                 // Measure the average duration of two calls...  

    17                 long start = System.nanoTime();

    18                 for (int i = 0; i < 2; i++) {

    19                     pattern.matcher(input).find();

    20                 }

    21                 System.out.println(input + ": " 

    22                        + ((System.nanoTime() - start) / 2000000d) 

    23                        + "ms");

    24             }

    25         }

    26     }

    27 }