String Levenshtein Distance - Java java.lang

Java examples for java.lang:String Distance

  1. HOME
  2. Java
  3. java.lang
  4. String Distance

Description

String Levenshtein Distance

Demo Code

/*/*from  ww  w . jav  a  2s  . c  o m*/
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        String s = "java2s.com";
        String t = "java2s.com";
        System.out.println(levDist(s, t));
    }

    static int levDist(String s, String t) {
        // degenerate cases
        if (s.equals(t))
            return 0;
        if (s.length() == 0)
            return t.length();
        if (t.length() == 0)
            return s.length();

        // create two work vectors of integer distances
        int[] v0 = new int[t.length() + 1];
        int[] v1 = new int[t.length() + 1];

        // initialize v0 (the previous row of distances)
        // this row is A[0][i]: edit distance for an empty s
        // the distance is just the number of characters to delete from t
        for (int i = 0; i < v0.length; i++)
            v0[i] = i;

        for (int i = 0; i < s.length(); i++) {
            // calculate v1 (current row distances) from the previous row v0

            // first element of v1 is A[i+1][0]
            //   edit distance is delete (i+1) chars from s to match empty t
            v1[0] = i + 1;

            // use formula to fill in the rest of the row
            for (int j = 0; j < t.length(); j++) {
                int cost = (s.charAt(i) == t.charAt(j)) ? 0 : 1;
                v1[j + 1] = Math.min(v1[j] + 1,
                        Math.min(v0[j + 1] + 1, v0[j] + cost));
            }

            // copy v1 (current row) to v0 (previous row) for next iteration
            System.arraycopy(v1, 0, v0, 0, v0.length);
        }

        return v1[t.length()];
    }
}

Related Tutorials