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

Credits:

Special thanks to  for adding this problem and creating all test cases.

 

Hide Tags

 

 

 

分析：将字符串中的每个数字提取出来，保存到数组中，然后逐个比较数组各个元素。

 

注意：“1” 和 “1.0” 以及“1.0.0” 是相同的，需要单独处理一下。。

 

也快参考 http://www.cnblogs.com/grandyang/p/4244123.html 

 

class Solution {    private:        int string2Int(const string& str)        {            if(str.size() == 0)                return 0;            int rtn = 0;            for(int i = 0; i < str.size(); i++)            {                rtn = rtn*10 + (str[i] - '0');            }            return rtn;        }        vector
     
       string2Ints(const string& str)        {            vector
      
        rtn;            if(str.size() == 0)                return rtn;            int size = str.size();            int left = 0;            int tmp;            for(int i = 0; i < size; i++)            {                if(str[i] == '.')                {                    tmp = string2Int(str.substr(left, i - left ));                    rtn.push_back(tmp);                    left = i + 1;                }            }            tmp = string2Int(str.substr(left, size + 1 - left ));            rtn.push_back(tmp);            return rtn;        }    public:        int compareVersion(string version1, string version2)        {            if(version1 == version2)                return false;            vector
       
         rtn1 = string2Ints(version1);            vector
        
          rtn2 = string2Ints(version2);            //printVector(rtn1);            //printVector(rtn2);            int size = min(rtn1.size(), rtn2.size());            for(int i = 0; i < size; i++)            {                if(rtn1[i] > rtn2[i] )                    return 1;                else if(rtn1[i] < rtn2[i] )                    return -1;            }            if(rtn1.size() == rtn2.size())                return 0;            else if(rtn1.size() > rtn2.size())            {                for(int i = size; i < rtn1.size(); i++)                {                    if(rtn1[i] != 0)                        return 1;                }                return 0;//all is zero            }            else //if(rtn1.size() < rtn2.size())            {                for(int i = size; i < rtn2.size(); i++)                {                    if(rtn2[i] != 0)                        return -1;                }                return 0;//all is zero            }        }};