Compare two version numbers version1 and version2.

If version1 > version2 return 1, if version1 < version2 return -1, otherwise return 0.

You may assume that the version strings are non-empty and contain only digits and the . character.

The . character does not represent a decimal point and is used to separate number sequences.

For instance, 2.5 is not “two and a half” or “half way to version three”, it is the fifth second-level revision of the second first-level revision.

Here is an example of version numbers ordering:

0.1 < 1.1 < 1.2 < 13.37

```public class Solution {
public int compareVersion(String version1, String version2) {
}
}```

This problem is selected from LeetCode.

## Solution

Convert the two version strings to multiple parts and convert the parts to values and compare them.

Be careful to some special cases such as: 0.0 is same to 0.0.0.0.

The solution below assumes that the next level is 0 if there are no more levels in the shorter version number.

```public class Solution {
public int compareVersion(String version1, String version2) {
String [] part1 = version1.split("\\.");
String [] part2 = version2.split("\\.");

int maxLength = Math.max(part1.length, part2.length);
for(int i=0; i < maxLength; i++) {
int v1 = i>=part1.length? 0: Integer.parseInt(part1[i]);
int v2 = i>=part2.length? 0: Integer.parseInt(part2[i]);
if(v1 > v2) return 1;
if(v1 < v2) return -1;
}
return 0;
}
}```