Dice's co-efficient

Dice.java

import java.util.*;
/**
 * Source: http://www.codeproject.com/Articles/147230/Simple-Fuzzy-String-Similarity-in-Java 
 * By George Stragand, 17 Jan 2011
 */
public class Dice {
  public static List<char[]> bigram(String input) {
    ArrayList<char[]> bigram = new ArrayList<char[]>();
    for (int i = 0; i < input.length() - 1; i++) {
      char[] chars = new char[2];
      chars[0] = input.charAt(i);
      chars[1] = input.charAt(i+1);
      bigram.add(chars);
    }
    return bigram;
  }

  public static double dice(List<char[]> bigram1, List<char[]> bigram2) {
    List<char[]> copy = new ArrayList<char[]>(bigram2);
    int matches = 0;
    for (int i = bigram1.size(); --i >= 0;) {
      char[] bigram = bigram1.get(i);
      for (int j = copy.size(); --j >= 0;) {
        char[] toMatch = copy.get(j);
        if (bigram[0] == toMatch[0] && bigram[1] == toMatch[1]) {
          copy.remove(j);
          matches += 2;
          break;
        }
      }
    }
    return (double) matches / (bigram1.size() + bigram2.size());
  }

  public static void main(String[] args) {
    String a = "Selam merhaba nasilsiniz";
    String b = "Slm nbr nslsnz ii u?";

    double dc = dice(bigram(a), bigram(b));
    System.out.println((int) (dc*100) + "%");
  }

}