org.apache.xmlbeans.impl.common.Levenshtein Maven / Gradle / Ivy
/* Copyright 2004 The Apache Software Foundation
*
* 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 org.apache.xmlbeans.impl.common;
public class Levenshtein
{
//****************************
// Get minimum of three values
//****************************
private static int minimum(int a, int b, int c)
{
int mi = a;
if (b < mi)
mi = b;
if (c < mi)
mi = c;
return mi;
}
//*****************************
// Compute Levenshtein distance
//*****************************
public static int distance(String s, String t)
{
int d[][]; // matrix
int n; // length of s
int m; // length of t
int i; // iterates through s
int j; // iterates through t
char s_i; // ith character of s
char t_j; // jth character of t
int cost; // cost
// Step 1
n = s.length();
m = t.length();
if (n == 0)
return m;
if (m == 0)
return n;
d = new int[n+1][m+1];
// Step 2
for (i = 0; i <= n; i++)
d[i][0] = i;
for (j = 0; j <= m; j++)
d[0][j] = j;
// Step 3
for (i = 1; i <= n; i++)
{
s_i = s.charAt (i - 1);
// Step 4
for (j = 1; j <= m; j++)
{
t_j = t.charAt(j - 1);
// Step 5
if (s_i == t_j)
cost = 0;
else
cost = 1;
// Step 6
d[i][j] = minimum(d[i-1][j]+1, d[i][j-1]+1, d[i-1][j-1] + cost);
}
}
// Step 7
return d[n][m];
}
}