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
解题思路：
先进行split，然后转为int比较即可，JAVA实现如下：
static public int compareVersion(String version1, String version2) {
String[] s1=version1.split("\\.");
String[] s2=version2.split("\\.");
int[] num1=new int[Math.max(s1.length, s2.length)];
int[] num2=new int[Math.max(s1.length, s2.length)];
for(int i=0;i<s1.length;i++)
num1[i]= Integer.valueOf(s1[i]);
for(int i=0;i<s2.length;i++)
num2[i]= Integer.valueOf(s2[i]);
for(int i=0;i<num1.length;i++){
if(num1[i]>num2[i])
return 1;
else if(num1[i]<num2[i])
return -1;
}
return 0;
}