Compare Version Numbers

Compare two version numbers version1 and version1.

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

本题特殊情况要考虑到。v1 和v1.0 的比较。

public class Solution {
    public int compareVersion(String version1, String version2) {
        String[] splits1=version1.split("\\.",-1);
        String[] splits2=version2.split("\\.",-1);
        int shortLength=Math.min(splits1.length,splits2.length);
        int longLength=Math.max(splits2.length,splits1.length);
        int i=0;
        for(i=0;i<shortLength;i++)
        {
            if(Integer.parseInt(splits1[i])<Integer.parseInt(splits2[i]))
            {
                return -1;
            }
            else if(Integer.parseInt(splits1[i])>Integer.parseInt(splits2[i]))
            {
                return 1;
            }
        }
        if(i==longLength)
        {
            return 0;
        }
        else
        {
            while(i<longLength)//如果两个版本号不同长度，但是是同一版本的情况，如v1.0 和v1
            {
                if(splits1.length==longLength)
                {
                    if(Integer.parseInt(splits1[i])!=0)
                    {
                        return 1;
                    }
                }
                else if(splits2.length==longLength)
                {
                    if(Integer.parseInt(splits2[i])!=0)
                    {
                        return -1;
                    }
                }
                i++;
            }
            return 0;
        }
    }
}