Compare two version numbersversion1andversion2.
Ifversion1>version2return 1, ifversion1<version2return -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,2.5is 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

Solution: 注意各种corner case，比如1与1.0.0，01.1与01.001

    public int compareVersion(String version1, String version2) {
        String[] parts1 = version1.split("\\.");
        String[] parts2 = version2.split("\\.");
        for (int i = 0; i < parts1.length || i < parts2.length; i++) {
            Integer part1 = i >= parts1.length ? 0 : Integer.valueOf(parts1[i]);
            Integer part2 = i >= parts2.length ? 0 : Integer.valueOf(parts2[i]);
            if (part1 != part2) {
                return part1.compareTo(part2);
            }
        }

        return 0;
    }