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

Solving method：

class Solution(object):
    def compareVersion(self, version1, version2):
        parts1 = [int(x) for x in version1.split('.')]
        parts2 = [int(x) for x in version2.split('.')]
   
        # fill up the shorter version with zeros ...
        lendiff = len(parts1) - len(parts2)
        if lendiff > 0:
            parts2.extend([0] * lendiff)
        elif lendiff < 0:
            parts1.extend([0] * (-lendiff))
   
        for i, p in enumerate(parts1):
            ret = cmp(p, parts2[i])
            if ret: return ret
        return 0