165. Compare Version Numbers

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

class Solution {
public:
vector<int> change(string version)
{
vector<int> m;
if(version.size()<=0)
return m;
int n=0;
while(version.find('.',n)!=-1)
{
int j=version.find('.',n);
string str=version.substr(n,j-n);
m.push_back(atoi(str.c_str()));
n=j+1;
}
string temp=version.substr(n);
int temp1=atoi(temp.c_str());
m.push_back(temp1);
return m;
}
int compareVersion(string version1, string version2)
{
vector<int> v1=change(version1);
vector<int> v2=change(version2);
for(int i=0;i<abs(v1.size()-v2.size());++i)
{
if(v1.size()<v2.size())
v1.push_back(0);
else
v2.push_back(0);
}
for(int i=0;i<max(v1.size(),v2.size());++i)
{
if(v1[i]<v2[i])
return -1;
if(v1[i]>v2[i])
return 1;
}
return 0;
}
};