_165.java

package com.fishercoder.solutions;
/**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 _165 {

    public static int compareVersion(String version1, String version2) {
        String[] v1s = version1.split("\\.");//escaping it is very important! Otherwise, it's not going to work as expected!
        String[] v2s = version2.split("\\.");
        int len = (v1s.length < v2s.length) ? v2s.length : v1s.length;
        for (int i = 0; i < len; i++) {
            if (v1s.length == i) {
                while (i < len) {
                    if (Integer.parseInt(v2s[i]) > 0) {
                        return -1;
                    }
                    i++;
                }
            } else if (v2s.length == i) {
                while (i < len) {
                    if (Integer.parseInt(v1s[i]) > 0) {
                        return 1;
                    }
                    i++;
                }
            } else {
                if (Integer.parseInt(v1s[i]) > Integer.parseInt(v2s[i])) {
                    return 1;
                } else if (Integer.parseInt(v2s[i]) > Integer.parseInt(v1s[i])) {
                    return -1;
                }
            }
        }
        return 0;
    }

    public static void main(String... args) {
//        String version1 = "1.1";
//        String version2 = "1.2";//should return -1

//        String version1 = "1.0.1";
//        String version2 = "1";//should return 1

        String version1 = "1.0";
        String version2 = "1";//should return 0

        /**"1.0.1", "1"*/
        System.out.println(compareVersion(version1, version2));
    }

}