Compare Version Numbers

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 < 1.13 < 1.13.4

import java.math.BigInteger;

public class Solution {
    public int compareVersion(String A, String B) {
        String[] s1 = A.split("\\.");
        String[] s2 = B.split("\\.");
        int i = 0;
        while (i < s1.length || i < s2.length) {
            BigInteger version1 = i < s1.length ? new BigInteger(s1[i]) : BigInteger.ZERO;
            BigInteger version2 = i < s2.length ? new BigInteger(s2[i]) : BigInteger.ZERO;
            int comparison = version1.compareTo(version2);
            if (comparison != 0)
                return comparison;
            i++;
        }
        return 0;
    }
}