Levenshtein Distance

Given 2 strings, find the minimum number of operations required to change one string to the other. An operation is defined as either replacement of a character, deletion of a character, or addition of a character. This problem is also called Levenshtein Distance. Levenshtein distance is a string metric for measuring the difference between two sequences.

Example

Input: 
str1 = 'abc'
str2 = 'yabd'

Output: 2

Explanation:

To convert abc to yabd, there are two ways:

• add character y to string abc at position str[0], replace character c to characterd at position str1[2]
• Remove character y at position str2[0], replace character d with character c at position str2[3].

Constraints

Input: 
1 <= str1.length <= 100
1 <= str2.length <= 100