levenshtein algorithm

dafenix · abranhe · commit b460f83157e1 · 2020-10-06T16:46:15.000-04:00
diff --git a/strings/LevenshteinDistance.java b/strings/LevenshteinDistance.java
@@ -0,0 +1,31 @@
+// Source: https://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Levenshtein_distance#Java
+public class LevenshteinDistance {
+  private static int minimum(int a, int b, int c) {
+    return Math.min(Math.min(a, b), c);
+  }
+
+
+  public static int computeLevenshteinDistance(CharSequence lhs, CharSequence rhs) {
+    int[][] distance = new int[lhs.length() + 1][rhs.length() + 1];
+
+    for (int i = 0; i <= lhs.length(); i++)
+      distance[i][0] = i;
+    for (int j = 1; j <= rhs.length(); j++)
+      distance[0][j] = j;
+
+    for (int i = 1; i <= lhs.length(); i++)
+      for (int j = 1; j <= rhs.length(); j++)
+        distance[i][j] = minimum(
+            distance[i - 1][j] + 1,
+            distance[i][j - 1] + 1,
+            distance[i - 1][j - 1] + ((lhs.charAt(i - 1) == rhs.charAt(j - 1)) ? 0 : 1));
+
+    return distance[lhs.length()][rhs.length()];
+  }
+  // Driver method to test above
+  public static void main(String args[]){
+    System.out.println("Distance from 'stull' to 'still' is :"+ LevenshteinDistance.computeLevenshteinDistance("stull", "still"));
+    System.out.println("Distance from 'stull' to 'steal' is :"+ LevenshteinDistance.computeLevenshteinDistance("stull", "steal"));
+    System.out.println("Distance from 'skill' to 'steal' is :"+ LevenshteinDistance.computeLevenshteinDistance("skill", "steal"));
+  }
+}
