diff --git a/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java b/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java index e3e221ea..f2a96187 100644 --- a/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java +++ b/src/main/java/com/thealgorithms/dynamicprogramming/LevenshteinDistance.java @@ -17,43 +17,40 @@ public class LevenshteinDistance { } } - private static int calculate_distance(String a, String b) { - int len_a = a.length() + 1; - int len_b = b.length() + 1; - int[][] distance_mat = new int[len_a][len_b]; - for (int i = 0; i < len_a; i++) { - distance_mat[i][0] = i; + public static int calculateLevenshteinDistance(String str1, String str2) { + int len1 = str1.length() + 1; + int len2 = str2.length() + 1; + int[][] distanceMat = new int[len1][len2]; + for (int i = 0; i < len1; i++) { + distanceMat[i][0] = i; } - for (int j = 0; j < len_b; j++) { - distance_mat[0][j] = j; + for (int j = 0; j < len2; j++) { + distanceMat[0][j] = j; } - for (int i = 0; i < len_a; i++) { - for (int j = 0; j < len_b; j++) { - int cost; - if (a.charAt(i) == b.charAt(j)) { - cost = 0; + for (int i = 1; i < len1; i++) { + for (int j = 1; j < len2; j++) { + if (str1.charAt(i - 1) == str2.charAt(j - 1)) { + distanceMat[i][j] = distanceMat[i - 1][j - 1]; } else { - cost = 1; + distanceMat[i][j] = + 1 + minimum( + distanceMat[i - 1][j], + distanceMat[i - 1][j - 1], + distanceMat[i][j - 1] + ); } - distance_mat[i][j] = - minimum( - distance_mat[i - 1][j], - distance_mat[i - 1][j - 1], - distance_mat[i][j - 1] - ) + - cost; } } - return distance_mat[len_a - 1][len_b - 1]; + return distanceMat[len1 - 1][len2 - 1]; } public static void main(String[] args) { - String a = ""; // enter your string here - String b = ""; // enter your string here + String str1 = ""; // enter your string here + String str2 = ""; // enter your string here System.out.print( - "Levenshtein distance between " + a + " and " + b + " is: " + "Levenshtein distance between " + str1 + " and " + str2 + " is: " ); - System.out.println(calculate_distance(a, b)); + System.out.println(calculateLevenshteinDistance(str1, str2)); } } diff --git a/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java b/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java new file mode 100644 index 00000000..4e3cfa3c --- /dev/null +++ b/src/test/java/com/thealgorithms/dynamicprogramming/LevenshteinDistanceTests.java @@ -0,0 +1,17 @@ +package com.thealgorithms.dynamicprogramming; + +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.CsvSource; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +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); + } + +}