prblm165.java

public class prblm165 {
    public static void main(String[] args) {
        String version1 = "1.2", version2 = "1.10";
        System.out.println(new prblm165().compareVersion(version1, version2));   
    }

    public int compareVersion(String version1, String version2) {
        for (int i = 0, j = 0; i < version1.length() || j < version2.length(); i++, j++) {
            int a = 0, b = 0;
            while (i < version1.length() && version1.charAt(i) != '.') {
                a = (a * 10) + (version1.charAt(i++) - '0');
            }
            while (j < version2.length() && version2.charAt(j) != '.') {
                b = (b * 10) + (version2.charAt(j++) - '0');
            }
            if(a != b){
                return a < b ? -1 : 1; 
            }
        }
        return 0;
    }
}