题目：
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
思路分析：
先将version字符串以点号分割放入vector中，然后将vector中的每个字符string类型转成int类型，然后依次进行int的比较。
C++示例代码：
class Solution
{
private:/*将str以ch进行分割，结果保存在vector中返回*/vector<string> split(string str, char ch){vector<string> result;int index = 0;int count = 0;string substr;for (int i = 0; i < str.length(); i++){if (str[i] == ch){count = i - index;substr = str.substr(index, count);index = i + 1;result.push_back(substr);}}count = str.length()- index;substr = str.substr(index, count);result.push_back(substr);return result;}/*将vector中的string类型转换成int类型这里使用到了库函数stoi()*/vector<int> toInt(vector<string> numbers){int size = numbers.size();vector<int> intnums;intnums.reserve(size);for (int i = 0; i < size; i++){intnums.push_back(stoi(numbers[i]));}return intnums;}public:int compareVersion(string version1, string version2){vector<string> strversion1 = split(version1, '.');vector<int> intversion1 = toInt(strversion1);vector<string> strversion2 = split(version2, '.');vector<int> intversion2 = toInt(strversion2);int size1 = intversion1.size();int size2 = intversion2.size();int size = size1;/*下面的ifelse是将两个vector的个数补齐，即使vector的 size是一样的，不足的补零。*/if (size1 > size2){size = size1;for (int i = size2; i < size; i++){intversion2.push_back(0);}}else if (size1 < size2){size = size2;for (int i = size1; i < size; i++){intversion1.push_back(0);}}for (int i = 0; i < size; i++){if (intversion1[i] > intversion2[i]){return 1;}else if (intversion1[i] < intversion2[i]){return -1;}}return 0;}
};