EditDistance.java

package com.dozuki.ifixit.util;


/**
 * Helper class to compute the edit distance for two Strings.
 *
 * Taken from: http://professorjava.weebly.com/edit-distance.html
 */
public class EditDistance {
   public static int editDistance(String s, String t) {
      int m = s.length();
      int n = t.length();
      int[][] d = new int[m + 1][n + 1];

      for (int i = 0; i <= m; i++) {
         d[i][0] = i;
      }

      for (int j = 0; j <= n; j++) {
         d[0][j] = j;
      }

      for (int j = 1; j <= n; j++) {
         for (int i = 1; i <= m; i++) {
            if (s.charAt(i - 1) == t.charAt(j - 1)) {
               d[i][j] = d[i - 1][j - 1];
            } else {
               d[i][j] = min(
                  d[i - 1][j],
                  d[i][j - 1],
                  d[i - 1][j - 1]
               ) + 1;
            }
         }
      }

      return d[m][n];
   }

   public static int min(int a, int b ,int c) {
      return Math.min(Math.min(a, b), c);
   }
}