**Info:**Returns the number of character edits (removals, inserts, replacements) that must occur to get from string A to string B.

Levenshtein distance computations~~Words:~~ant, aunt~~Levenshtein distance:~~1 Note: Only 1 edit is needed. The 'u' must be added at index 2.~~Words:~~Samantha, Sam~~Levenshtein distance:~~5 Note: The final 5 letters must be removed.~~Words:~~Flomax, Volmax~~Levenshtein distance:~~3 Note: The first 3 letters must be changed Drug names are commonly confused.

**Tip:**The two-dimensional array requires fewer allocations upon the managed heap and may be faster in this context.

C# program that implements the algorithmusing System;/// <summary> /// Contains approximate string matching /// </summary>static class LevenshteinDistance {/// <summary> /// Compute the distance between two strings. /// </summary>public static int Compute(string s, string t) { int n = s.Length; int m = t.Length; int[,] d = new int[n + 1, m + 1];// Step 1if (n == 0) { return m; } if (m == 0) { return n; }// Step 2for (int i = 0; i <= n; d[i, 0] = i++) { } for (int j = 0; j <= m; d[0, j] = j++) { }// Step 3for (int i = 1; i <= n; i++) {//Step 4for (int j = 1; j <= m; j++) {// Step 5int cost = (t[j - 1] == s[i - 1]) ? 0 : 1;// Step 6d[i, j] = Math.Min( Math.Min(d[i - 1, j] + 1, d[i, j - 1] + 1), d[i - 1, j - 1] + cost); } }// Step 7return d[n, m]; } } class Program { static void Main() { Console.WriteLine(LevenshteinDistance.Compute("aunt", "ant")); Console.WriteLine(LevenshteinDistance.Compute("Sam", "Samantha")); Console.WriteLine(LevenshteinDistance.Compute("flomax", "volmax")); } }Output1 5 3

**Tip:**You can verify the implementation is the standard version of Levenshtein by looking at a computer science textbook.

C# program that calls Levenshtein in loopstatic void Main() { List<string[]> l = new List<string[]> { new string[]{"ant", "aunt"}, new string[]{"Sam", "Samantha"}, new string[]{"clozapine", "olanzapine"}, new string[]{"flomax", "volmax"}, new string[]{"toradol", "tramadol"}, new string[]{"kitten", "sitting"} }; foreach (string[] a in l) { int cost = Compute(a[0], a[1]); Console.WriteLine("{0} -> {1} = {2}", a[0], a[1], cost); } }Outputant -> aunt = 1 Sam -> Samantha = 5 clozapine -> olanzapine = 3 flomax -> volmax = 3 toradol -> tramadol = 3 kitten -> sitting = 3