Java Program to Implement Wagner and Fisher Algorithm for online String Matching

This is a java program to implement Wagner and Fisher Algorithm. In computer science, the Wagner–Fischer algorithm is a dynamic programming algorithm that computes the edit distance between two strings of characters.

Here is the source code of the Java Program to Implement Wagner and Fisher Algorithm for online String Matching. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

package com.maixuanviet.setandstring;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class WagnerandFischer
{
    public int getLevenshteinDistance(String str1, String str2)
    {
        int len1 = str1.length();
        int len2 = str2.length();
        int[][] arr = new int[len1 + 1][len2 + 1];
        for (int i = 0; i <= len1; i++)
            arr[i][0] = i;
        for (int i = 1; i <= len2; i++)
            arr[0][i] = i;
        for (int i = 1; i <= len1; i++)
        {
            for (int j = 1; j <= len2; j++)
            {
                int m = (str1.charAt(i - 1) == str2.charAt(j - 1)) ? 0 : 1;
                arr[i][j] = Math.min(
                        Math.min(arr[i - 1][j] + 1, arr[i][j - 1] + 1),
                        arr[i - 1][j - 1] + m);
            }
        }
        return arr[len1][len2];
    }
 
    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Enter string 1 :");
        String str1 = br.readLine();
        System.out.println("Enter string 2 :");
        String str2 = br.readLine();
        WagnerandFischer wf = new WagnerandFischer();
        int lDist = wf.getLevenshteinDistance(str1, str2);
        System.out.println("Edit (Levenshtein) Distance between two strings = "
                + lDist);
        br.close();
    }
}

Output:

$ javac WagnerandFischer.java
$ java WagnerandFischer
 
Enter string 1 :
Wagner and Fisher Algorithm
Enter string 2 :
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Edit (Levenshtein) Distance between two strings = 844