LevenshteinDistanceSnippet.java

/*
 * MIT License
 *
 * Copyright (c) 2017-2022 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package string;

/**
 * LevenshteinDistanceSnippet.
 */
public class LevenshteinDistanceSnippet {

  /**
   * Find the Levenshtein distance between two words. https://en.wikipedia.org/wiki/Levenshtein_distance
   *
   * @param word1 first word
   * @param word2 second word
   * @return distance
   */
  public static int findLevenshteinDistance(String word1, String word2) {
    // If word2 is empty, removing
    int[][] ans = new int[word1.length() + 1][word2.length() + 1];
    for (int i = 0; i <= word1.length(); i++) {
      ans[i][0] = i;
    }
    // if word1 is empty, adding
    for (int i = 0; i <= word2.length(); i++) {
      ans[0][i] = i;
    }
    // None is empty
    for (int i = 1; i <= word1.length(); i++) {
      for (int j = 1; j <= word2.length(); j++) {
        int min = Math.min(Math.min(ans[i][j - 1], ans[i - 1][j]), ans[i - 1][j - 1]);
        ans[i][j] = word1.charAt(i - 1) == word2.charAt(j - 1) ? ans[i - 1][j - 1] : min + 1;
      }
    }
    return ans[word1.length()][word2.length()];
  }
}