Refactor Levenshtein distance implementation (#5138)

* ref: refactor Levenshtein distance implementation
- Rewrite the original levenshtein distance implementation in functional style
- Add optimized version of levenshtein distance

* ref: make `LevenshteinDistance` class a proper utility

* ref: remove duplicated test data

* ref: update tests

---

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java

@@ -2,15 +2,44 @@ package com.thealgorithms.dynamicprogramming;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.ToIntBiFunction;
+import java.util.stream.Stream;
 import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
 public class LevenshteinDistanceTests {
 
     @ParameterizedTest
-    @CsvSource({"dog,cat,3", "sunday,saturday,3", "cat,cats,1", "rain,train,1"})
-    void levenshteinDistanceTest(String str1, String str2, int distance) {
-        int result = LevenshteinDistance.calculateLevenshteinDistance(str1, str2);
-        assertEquals(distance, result);
+    @MethodSource("testCases")
+    public void testLevenshteinDistance(final int expected, final String str1, final String str2, final ToIntBiFunction<String, String> dist) {
+        assertEquals(expected, dist.applyAsInt(str1, str2));
+        assertEquals(expected, dist.applyAsInt(str2, str1));
+        assertEquals(0, dist.applyAsInt(str1, str1));
+        assertEquals(0, dist.applyAsInt(str2, str2));
+    }
+
+    private static Stream<Arguments> testCases() {
+        final Object[][] testData = {
+            {0, "", ""},
+            {0, "Hello, World!", "Hello, World!"},
+            {4, "", "Rust"},
+            {3, "horse", "ros"},
+            {6, "tan", "elephant"},
+            {8, "execute", "intention"},
+            {1, "a", "b"},
+            {1, "a", "aa"},
+            {1, "a", ""},
+            {1, "a", "ab"},
+            {1, "a", "ba"},
+            {2, "a", "bc"},
+            {2, "a", "cb"},
+        };
+
+        final List<ToIntBiFunction<String, String>> methods = Arrays.asList(LevenshteinDistance::naiveLevenshteinDistance, LevenshteinDistance::optimizedLevenshteinDistance);
+
+        return Stream.of(testData).flatMap(input -> methods.stream().map(method -> Arguments.of(input[0], input[1], input[2], method)));
     }
 }