#ADVEDIST. Advanced Edit Distance
Advanced Edit Distance
The edit distance of two strings S and T is the minimum number of edit operations that need to be done to transform S into T . The valid edit operations are:
- Insert a single character at any position.
- Modify an existing character.
- Remove an existing character.
For example, the edit distance of “pantera” and “aorta” is 5, because the following chain of edits is valid (and there is no shorter chain):
“pantera” → “antera” → “aotera” → “aoera” → “aora” → “aorta”.
We define the advanced edit distance in a similar way, but adding the swap of two adjacent characters as an extra valid operation. With this setting, the advanced edit distance of “pantera” and “aorta” is 4:
“pantera” → “antera” → “antra” → “aotra” → “aorta”.
You need to write a program that calculates the advanced edit distance of two given words.
Input
The input contains several test cases. Each test case is described in a single line that contains two non-empty words, each of them of at most 1000 lowercase letters, separated by a single space. The last line of the input contains two asterisks separated by a single space and should not be processed as a test case.
Output
For each test case output a single line with an integer representing the advanced edit distance of the two input words.
Example
Input: pantera aorta zero zero * *</p>Output: 4 0