165. Compare Version Numbers

Compare two version numbers version1 andversion2.
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

注意：“.”在正则中表示任何字符，因此只单纯的考虑“.”这个符号时，应该使用转义。

public class Solution {    public int compareVersion(String version1, String version2) {        String[] ver1=version1.split("\\.");        String[] ver2=version2.split("\\.");        int n1=ver1.length;        int n2=ver2.length;        int n=n1<n2?n1:n2;        for(int i=0;i<n;i++){            if(Integer.parseInt(ver1[i])<Integer.parseInt(ver2[i])) return -1;            if(Integer.parseInt(ver1[i])>Integer.parseInt(ver2[i])) return 1;        }        for(int i=n;i<n1;i++){            if(Integer.parseInt(ver1[i])!=0)                return 1;        }        for(int i=n;i<n2;i++){            if(Integer.parseInt(ver2[i])!=0)                return -1;        }               return 0;    }}