Java 字符串相似度算法

package com;

public class DistanceScore {
    public static void main(String[] args) {
        System.out.println(score("hello", "hello"));

    }
    static double score(String word , String word2){
        int w1 = word.length(); //横
         int w2 = word2.length(); //纵
        int [][] arr = new int[w1+1][w2+1];
        if(w1 == 0 || w2 == 0)
            return (1 - 0);
        for (int i = 0; i < w1; i++) {
            arr[i][0] = i ;
        }
        for (int i = 0; i < w2; i++) {
            arr[0][i] = i ;
        }
        for (int i = 1; i <= w1; i++) {
            int cost = 1 ;
            char ch1 = word.charAt(i - 1);
            for (int j = 1; j <= w2; j++) {
                char ch2 = word2.charAt(j - 1 );
                if(ch1 == ch2 )
                    cost = 0 ;
                arr[i][j] = Math.min(Math.min(arr[i-1][j] + 1, arr[i][j-1] + 1 ) , arr[i-1][j-1] + cost);
            }
        }
        return 1 - (double)arr[w1][w2] / Math.max(w1, w2) ;
    }
}