Calculate Levenshtein Distance - Java java.lang

Java examples for java.lang:Math Algorithm

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Description

Calculate Levenshtein Distance

Demo Code


//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        String s0 = "java2s.com";
        String s1 = "java2s.com";
        System.out.println(CALCULATE_LEVENSHTEIN_DISTANCE(s0, s1));
    }//from   ww w. j a  v  a 2 s .com

    static int CALCULATE_LEVENSHTEIN_DISTANCE(String s0, String s1) {
        int len0 = s0.length() + 1;
        int len1 = s1.length() + 1;

        // the array of distances
        int[] cost = new int[len0];
        int[] newcost = new int[len0];

        // initial cost of skipping prefix in String s0
        for (int i = 0; i < len0; i++) {
            cost[i] = i;
        }

        // dynamically computing the array of distances

        // transformation cost for each letter in s1
        for (int j = 1; j < len1; j++) {
            // initial cost of skipping prefix in String s1
            newcost[0] = j;

            // transformation cost for each letter in s0
            for (int i = 1; i < len0; i++) {
                // matching current letters in both strings
                int match = (s0.charAt(i - 1) == s1.charAt(j - 1)) ? 0 : 1;

                // computing cost for each transformation
                int cost_replace = cost[i - 1] + match;
                int cost_insert = cost[i] + 1;
                int cost_delete = newcost[i - 1] + 1;

                // keep minimum cost
                newcost[i] = Math.min(Math.min(cost_insert, cost_delete),
                        cost_replace);
            }

            // swap cost/newcost arrays
            int[] swap = cost;
            cost = newcost;
            newcost = swap;
        }

        // the distance is the cost for transforming all letters in both strings
        return cost[len0 - 1];
    }
}

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