public static int LevenshteinDistance(this string str, string compare, bool caseSensitive = true)
{
if (!caseSensitive)
{
str = str.ToLower();
compare = compare.ToLower();
}
var sLen = str.Length;
var cLen = compare.Length;
var result = new int[sLen + 1, cLen + 1];
if (sLen == 0)
return cLen;
if (cLen == 0)
return sLen;
for (int i = 0; i <= sLen; result[i, 0] = i++) ;
for (int i = 0; i <= cLen; result[0, i] = i++) ;
for (int i = 1; i <= sLen; i++)
{
for (int j = 1; j <= cLen; j++)
{
var cost = (compare[j - 1] == str[i - 1]) ? 0 : 1;
result[i, j] = Math.Min(Math.Min(result[i - 1, j] + 1, result[i, j - 1] + 1), result[i - 1, j - 1] + cost);
}
}
return result[sLen, cLen];
}