Levenshtein.java

/*******************************************************************************
 * Breakout Cave Survey Visualizer
 *
 * Copyright (C) 2014 James Edwards
 *
 * jedwards8 at fastmail dot fm
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *******************************************************************************/
package org.andork.util;

public class Levenshtein {
	public static int distance(String a, String b) {
		int d[][] = new int[a.length() + 1][b.length() + 1];

		for (int i = 1; i <= a.length(); i++) {
			d[i][0] = i;
		}
		for (int j = 1; j <= b.length(); j++) {
			d[0][j] = j;
		}

		for (int j = 1; j <= b.length(); j++) {
			for (int i = 1; i <= a.length(); i++) {
				if (a.charAt(i - 1) == b.charAt(j - 1)) {
					d[i][j] = d[i - 1][j - 1];
				} else {
					d[i][j] = Math.min(d[i - 1][j] + 1, Math.min(d[i][j - 1] + 1, d[i - 1][j - 1] + 1));
				}
			}
		}

		return d[a.length()][b.length()];
	}

	private Levenshtein() {

	}
}