code: public class Levenshtein {
  
      public static int distance(String a, String b) {
          a = a.toLowerCase();
          b = b.toLowerCase();
          // i == 0
          int [] costs = new int [b.length() + 1];
          for (int j = 0; j < costs.length; j++)
              costs[j] = j;
          for (int i = 1; i <= a.length(); i++) {
              // j == 0; nw = lev(i - 1, j)
              costs[0] = i;
              int nw = i - 1;
              for (int j = 1; j <= b.length(); j++) {
                  int cj = Math.min(1 + Math.min(costs[j], costs[j - 1]), a.charAt(i - 1) == b.charAt(j - 1) ? nw : nw + 1);
                  nw = costs[j];
                  costs[j] = cj;
              }
          }
          return costs[b.length()];
      }
  
      public static void main(String [] args) {
          String [] data = { "kitten", "sitting", "saturday", "sunday", "rosettacode", "raisethysword" };
          for (int i = 0; i < data.length; i += 2)
              System.out.println("distance(" + data[i] + ", " + data[i+1] + ") = " + distance(data[i], data[i+1]));
      }
  }
  