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 < 13.37

Credits:Special thanks to @ts for adding this problem and creating all test cases.

Solution

public class Solution {
      public int compareVersion(String version1, String version2) {
        String[] v1 = version1.split("\\.");
        String[] v2 = version2.split("\\.");

        int index1 = 0;
        int index2 = 0;

        while (index1 < v1.length || index2 < v2.length) {
            int a = index1 < v1.length ? Integer.valueOf(v1[index1]) : 0;
            int b = index2 < v2.length ? Integer.valueOf(v2[index2]) : 0;

            if (a < b) return -1;
            else if (a > b) return 1;

            index1++;
            index2++;
        }

        return 0;
    }
}